clean-up filters to adhere to flake8 (#118)

Signed-off-by: Matthew Peveler <matt.peveler@gmail.com>

8 files changed, 249 insertions, 151 deletions

diff --git a/asciidocapi.py b/asciidocapi.py
index 84bbcfd..745aa10 100644
--- a/asciidocapi.py
+++ b/asciidocapi.py
@@ -52,7 +52,9 @@ under the terms of the GNU General Public License (GPL).
 
 """
 
-import sys,os,re
+import sys
+import os
+import re
 
 API_VERSION = '0.1.2'
 MIN_ASCIIDOC_VERSION = '8.4.1'  # Minimum acceptable AsciiDoc version.
@@ -82,13 +84,15 @@ class Options(object):
     """
     def __init__(self, values=[]):
         self.values = values[:]
+
     def __call__(self, name, value=None):
         """Shortcut for append method."""
         self.append(name, value)
+
     def append(self, name, value=None):
-        if type(value) in (int,float):
+        if type(value) in (int, float):
             value = str(value)
-        self.values.append((name,value))
+        self.values.append((name, value))
 
 
 class Version(object):
@@ -159,7 +163,9 @@ class Version(object):
         return True
 
     def __eq__(self, other):
-        if self.major == other.major and self.minor == other.minor and self.micro == other.micro:
+        if self.major == other.major \
+                and self.minor == other.minor \
+                and self.micro == other.micro:
             return True
 
         return False
@@ -194,18 +200,21 @@ class AsciiDocAPI(object):
         else:
             # try to find sibling paths
             this_path = os.path.dirname(os.path.realpath(__file__))
-            for fname in ['asciidoc.py','asciidoc.pyc','asciidoc']:
+            for fname in ['asciidoc.py', 'asciidoc.pyc', 'asciidoc']:
                 cmd = find_in_path(fname, path=this_path)
-                if cmd: break
+                if cmd:
+                    break
             else:
                 # Try shell search paths.
-                for fname in ['asciidoc.py','asciidoc.pyc','asciidoc']:
+                for fname in ['asciidoc.py', 'asciidoc.pyc', 'asciidoc']:
                     cmd = find_in_path(fname)
-                    if cmd: break
+                    if cmd:
+                        break
                 else:
                     # Finally try current working directory.
-                    for cmd in ['asciidoc.py','asciidoc.pyc','asciidoc']:
-                        if os.path.isfile(cmd): break
+                    for cmd in ['asciidoc.py', 'asciidoc.pyc', 'asciidoc']:
+                        if os.path.isfile(cmd):
+                            break
                     else:
                         raise AsciiDocError('failed to locate asciidoc')
         self.cmd = os.path.realpath(cmd)
@@ -219,7 +228,7 @@ class AsciiDocAPI(object):
         for an explanation of why a seemingly straight-forward job turned out
         quite complicated.
         '''
-        if os.path.splitext(self.cmd)[1] in ['.py','.pyc']:
+        if os.path.splitext(self.cmd)[1] in ['.py', '.pyc']:
             sys.path.insert(0, os.path.dirname(self.cmd))
             try:
                 try:
diff --git a/filters/code/code-filter.py b/filters/code/code-filter.py
index ac9e775..40689c7 100755
--- a/filters/code/code-filter.py
+++ b/filters/code/code-filter.py
@@ -50,7 +50,9 @@ COPYING
     granted under the terms of the GNU General Public License (GPL).
 '''
 
-import os, sys, re
+import os
+import sys
+import re
 
 VERSION = '1.1.2'
 
@@ -60,52 +62,58 @@ backend = None
 tabsize = 8
 keywordtags = {
     'html':
-        ('<strong>','</strong>'),
+        ('<strong>', '</strong>'),
     'css':
-        ('<strong>','</strong>'),
+        ('<strong>', '</strong>'),
     'docbook':
-        ('<emphasis role="strong">','</emphasis>'),
+        ('<emphasis role="strong">', '</emphasis>'),
     'linuxdoc':
-        ('','')
+        ('', '')
 }
 commenttags = {
     'html':
-        ('<i>','</i>'),
+        ('<i>', '</i>'),
     'css':
-        ('<i>','</i>'),
+        ('<i>', '</i>'),
     'docbook':
-        ('<emphasis>','</emphasis>'),
+        ('<emphasis>', '</emphasis>'),
     'linuxdoc':
-        ('','')
+        ('', '')
 }
 keywords = {
     'python':
-         ('and', 'del', 'for', 'is', 'raise', 'assert', 'elif', 'from',
-         'lambda', 'return', 'break', 'else', 'global', 'not', 'try', 'class',
-         'except', 'if', 'or', 'while', 'continue', 'exec', 'import', 'pass',
-         'yield', 'def', 'finally', 'in', 'print'),
+        (
+            'and', 'del', 'for', 'is', 'raise', 'assert', 'elif', 'from',
+            'lambda', 'return', 'break', 'else', 'global', 'not', 'try', 'class',
+            'except', 'if', 'or', 'while', 'continue', 'exec', 'import', 'pass',
+            'yield', 'def', 'finally', 'in', 'print'
+        ),
     'ruby':
-        ('__FILE__', 'and', 'def', 'end', 'in', 'or', 'self', 'unless',
-        '__LINE__', 'begin', 'defined?' 'ensure', 'module', 'redo', 'super',
-        'until', 'BEGIN', 'break', 'do', 'false', 'next', 'rescue', 'then',
-        'when', 'END', 'case', 'else', 'for', 'nil', 'retry', 'true', 'while',
-        'alias', 'class', 'elsif', 'if', 'not', 'return', 'undef', 'yield'),
+        (
+            '__FILE__', 'and', 'def', 'end', 'in', 'or', 'self', 'unless',
+            '__LINE__', 'begin', 'defined?' 'ensure', 'module', 'redo', 'super',
+            'until', 'BEGIN', 'break', 'do', 'false', 'next', 'rescue', 'then',
+            'when', 'END', 'case', 'else', 'for', 'nil', 'retry', 'true', 'while',
+            'alias', 'class', 'elsif', 'if', 'not', 'return', 'undef', 'yield'
+        ),
     'c++':
-        ('asm', 'auto', 'bool', 'break', 'case', 'catch', 'char', 'class',
-        'const', 'const_cast', 'continue', 'default', 'delete', 'do', 'double',
-        'dynamic_cast', 'else', 'enum', 'explicit', 'export', 'extern',
-        'false', 'float', 'for', 'friend', 'goto', 'if', 'inline', 'int',
-        'long', 'mutable', 'namespace', 'new', 'operator', 'private',
-        'protected', 'public', 'register', 'reinterpret_cast', 'return',
-        'short', 'signed', 'sizeof', 'static', 'static_cast', 'struct',
-        'switch', 'template', 'this', 'throw', 'true', 'try', 'typedef',
-        'typeid', 'typename', 'union', 'unsigned', 'using', 'virtual', 'void',
-        'volatile', 'wchar_t', 'while')
+        (
+            'asm', 'auto', 'bool', 'break', 'case', 'catch', 'char', 'class',
+            'const', 'const_cast', 'continue', 'default', 'delete', 'do', 'double',
+            'dynamic_cast', 'else', 'enum', 'explicit', 'export', 'extern',
+            'false', 'float', 'for', 'friend', 'goto', 'if', 'inline', 'int',
+            'long', 'mutable', 'namespace', 'new', 'operator', 'private',
+            'protected', 'public', 'register', 'reinterpret_cast', 'return',
+            'short', 'signed', 'sizeof', 'static', 'static_cast', 'struct',
+            'switch', 'template', 'this', 'throw', 'true', 'try', 'typedef',
+            'typeid', 'typename', 'union', 'unsigned', 'using', 'virtual', 'void',
+            'volatile', 'wchar_t', 'while'
+        )
 }
 block_comments = {
-    'python': ("'''","'''"),
+    'python': ("'''", "'''"),
     'ruby': None,
-    'c++': ('/*','*/')
+    'c++': ('/*', '*/')
 }
 inline_comments = {
     'python': '#',
@@ -113,54 +121,60 @@ inline_comments = {
     'c++': '//'
 }
 
+
 def print_stderr(line):
     sys.stderr.write(line+os.linesep)
 
+
 def sub_keyword(mo):
     '''re.subs() argument to tag keywords.'''
     word = mo.group('word')
     if word in keywords[language]:
-        stag,etag = keywordtags[backend]
+        stag, etag = keywordtags[backend]
         return stag+word+etag
     else:
         return word
 
+
 def code_filter():
     '''This function does all the work.'''
     global language, backend
     inline_comment = inline_comments[language]
     blk_comment = block_comments[language]
     if blk_comment:
-        blk_comment = (re.escape(block_comments[language][0]),
-            re.escape(block_comments[language][1]))
-    stag,etag = commenttags[backend]
+        blk_comment = (
+            re.escape(block_comments[language][0]),
+            re.escape(block_comments[language][1])
+        )
+    stag, etag = commenttags[backend]
     in_comment = 0  # True if we're inside a multi-line block comment.
-    tag_comment = 0 # True if we should tag the current line as a comment.
+    tag_comment = 0  # True if we should tag the current line as a comment.
     line = sys.stdin.readline()
     while line:
         line = line.rstrip()
         line = line.expandtabs(tabsize)
         # Escape special characters.
-        line = line.replace('&','&amp;')
-        line = line.replace('<','&lt;')
-        line = line.replace('>','&gt;')
+        line = line.replace('&', '&amp;')
+        line = line.replace('<', '&lt;')
+        line = line.replace('>', '&gt;')
         # Process block comment.
         if blk_comment:
             if in_comment:
-                if re.match(r'.*'+blk_comment[1]+r'$',line):
+                if re.match(r'.*'+blk_comment[1]+r'$', line):
                     in_comment = 0
             else:
-                if re.match(r'^\s*'+blk_comment[0]+r'.*'+blk_comment[1],line):
+                if re.match(r'^\s*'+blk_comment[0]+r'.*'+blk_comment[1], line):
                     # Single line block comment.
                     tag_comment = 1
-                elif re.match(r'^\s*'+blk_comment[0],line):
+                elif re.match(r'^\s*'+blk_comment[0], line):
                     # Start of multi-line block comment.
                     tag_comment = 1
                     in_comment = 1
                 else:
                     tag_comment = 0
         if tag_comment:
-            if line: line = stag+line+etag
+            if line:
+                line = stag+line+etag
         else:
             if inline_comment:
                 pos = line.find(inline_comment)
@@ -168,45 +182,51 @@ def code_filter():
                 pos = -1
             if pos >= 0:
                 # Process inline comment.
-                line = re.sub(r'\b(?P<word>\w+)\b',sub_keyword,line[:pos]) \
+                line = re.sub(r'\b(?P<word>\w+)\b', sub_keyword, line[:pos]) \
                     + stag + line[pos:] + etag
             else:
-                line = re.sub(r'\b(?P<word>\w+)\b',sub_keyword,line)
+                line = re.sub(r'\b(?P<word>\w+)\b', sub_keyword, line)
         sys.stdout.write(line + os.linesep)
         line = sys.stdin.readline()
 
+
 def usage(msg=''):
     if msg:
         print_stderr(msg)
     print_stderr('Usage: code-filter -b backend -l language [ -t tabsize ]')
     print_stderr('                   [ --help | -h ] [ --version | -v ]')
 
+
 def main():
     global language, backend, tabsize
     # Process command line options.
     import getopt
-    opts,args = getopt.getopt(sys.argv[1:],
+    opts, args = getopt.getopt(
+        sys.argv[1:],
         'b:l:ht:v',
-        ['help','version'])
+        ['help', 'version']
+    )
     if len(args) > 0:
         usage()
         sys.exit(1)
-    for o,v in opts:
-        if o in ('--help','-h'):
+    for o, v in opts:
+        if o in ('--help', '-h'):
             print(__doc__)
             sys.exit(0)
-        if o in ('--version','-v'):
+        if o in ('--version', '-v'):
             print('code-filter version %s' % (VERSION,))
             sys.exit(0)
-        if o == '-b': backend = v
+        if o == '-b':
+            backend = v
         if o == '-l':
             v = v.lower()
-            if v == 'c': v = 'c++'
+            if v == 'c':
+                v = 'c++'
             language = v
         if o == '-t':
             try:
                 tabsize = int(v)
-            except:
+            except BaseException:
                 usage('illegal tabsize')
                 sys.exit(1)
             if tabsize <= 0:
@@ -227,13 +247,16 @@ def main():
     # Do the work.
     code_filter()
 
+
 if __name__ == "__main__":
     try:
         main()
     except (KeyboardInterrupt, SystemExit):
         pass
-    except:
-        print_stderr("%s: unexpected exit status: %s" %
-            (os.path.basename(sys.argv[0]), sys.exc_info()[1]))
+    except BaseException:
+        print_stderr(
+            "%s: unexpected exit status: %s" %
+            (os.path.basename(sys.argv[0]), sys.exc_info()[1])
+        )
     # Exit with previous sys.exit() status or zero if no sys.exit().
     sys.exit(sys.exc_info()[1])
diff --git a/filters/graphviz/graphviz2png.py b/filters/graphviz/graphviz2png.py
index 0035843..a13c67d 100755
--- a/filters/graphviz/graphviz2png.py
+++ b/filters/graphviz/graphviz2png.py
@@ -1,19 +1,6 @@
 #!/usr/bin/env python3
 
-import os
-import sys
-import subprocess
-import argparse
-
-__AUTHOR__ = "Gouichi Iisaka <iisaka51@gmail.com>"
-__VERSION__ = '1.1.5'
-
-class EApp(Exception):
-    '''Application specific exception.'''
-    pass
-
-class Application():
-    '''
+'''
 NAME
     graphviz2png - Converts textual graphviz notation to PNG file
 
@@ -63,12 +50,32 @@ LICENSE
     Copyright (C) 2008-2009 Gouichi Iisaka.
     Free use of this software is granted under the terms of
     the GNU General Public License (GPL).
-    '''
+'''
 
+import os
+import sys
+import subprocess
+import argparse
+
+__AUTHOR__ = "Gouichi Iisaka <iisaka51@gmail.com>"
+__VERSION__ = '1.1.5'
+
+
+class EApp(Exception):
+    '''Application specific exception.'''
+    pass
+
+
+class Application():
     def __init__(self, argv=None):
         # Run dot, get the list of supported formats. It's prefixed by some junk.
-        format_output = subprocess.Popen(["dot", "-T?"], stderr=subprocess.PIPE, stdout=subprocess.PIPE).communicate()[1].decode('utf-8')
-        # The junk contains : and ends with :. So we split it, then strip the final endline, then split the list for future usage.
+        format_output = subprocess.Popen(
+            ["dot", "-T?"],
+            stderr=subprocess.PIPE,
+            stdout=subprocess.PIPE
+        ).communicate()[1].decode('utf-8')
+        # The junk contains : and ends with :. So we split it, then strip the
+        # final endline, then split the list for future usage.
         supported_formats = format_output.split(": ")[2][:-1].split(" ")
 
         if not argv:
@@ -79,13 +86,25 @@ LICENSE
         self.version += 'Copyright(c) 2008-2009: %s\n' % __AUTHOR__
 
         self.parser = argparse.ArgumentParser(usage=self.usage)
-        self.parser.add_argument("-o", "--outfile", action="store", dest="outfile", help="Output file")
-        self.parser.add_argument("-L", "--layout", action="store", dest="layout", default="dot",
-                                 choices=['dot', 'neato', 'twopi', 'circo', 'fdp'], help="Layout type")
-        self.parser.add_argument("-F", "--format", action="store", dest="format", default="png",
-                                 choices=supported_formats, help="Format type")
-        self.parser.add_argument("--debug", action="store_true", dest="do_debug", help=argparse.SUPPRESS)
-        self.parser.add_argument("-v", "--verbose", action="store_true", dest="do_verbose", default=False, help="verbose output")
+        self.parser.add_argument(
+            "-o", "--outfile", action="store", dest="outfile", help="Output file"
+        )
+        self.parser.add_argument(
+            "-L", "--layout", action="store", dest="layout", default="dot",
+            choices=['dot', 'neato', 'twopi', 'circo', 'fdp'], help="Layout type"
+        )
+        self.parser.add_argument(
+            "-F", "--format", action="store", dest="format", default="png",
+            choices=supported_formats, help="Format type"
+        )
+        self.parser.add_argument(
+            "--debug", action="store_true", dest="do_debug", help=argparse.SUPPRESS
+        )
+        self.parser.add_argument(
+            "-v", "--verbose",
+            action="store_true", dest="do_verbose", default=False,
+            help="verbose output"
+        )
         self.parser.add_argument("infile", action="store", help="Input file")
         self.parser.add_argument('--version', action='version', version=self.version)
         self.options = self.parser.parse_args()
@@ -112,7 +131,12 @@ LICENSE
         saved_cwd = os.getcwd()
         os.chdir(outdir)
         try:
-            cmd = '%s -T%s "%s" > "%s"' % (self.options.layout, self.options.format, infile, outfile)
+            cmd = '%s -T%s "%s" > "%s"' % (
+                self.options.layout,
+                self.options.format,
+                infile,
+                outfile
+            )
             self.systemcmd(cmd)
         finally:
             os.chdir(saved_cwd)
@@ -147,6 +171,7 @@ LICENSE
         if self.options.infile == '-':
             sys.stdout.write(' ')
 
+
 if __name__ == "__main__":
     app = Application()
     app.run()
diff --git a/filters/latex/latex2img.py b/filters/latex/latex2img.py
index 8e03614..a446dd7 100755
--- a/filters/latex/latex2img.py
+++ b/filters/latex/latex2img.py
@@ -58,7 +58,9 @@ COPYING
     granted under the terms of the MIT License.
 '''
 
-import os, sys, tempfile
+import os
+import sys
+import tempfile
 from hashlib import md5
 
 VERSION = '0.2.0'
@@ -80,27 +82,34 @@ TEX_FOOTER = r'''\end{document}'''
 # Globals.
 verbose = False
 
-class EApp(Exception): pass     # Application specific exception.
+
+class EApp(Exception):
+    pass     # Application specific exception.
+
 
 def print_stderr(line):
     sys.stderr.write(line + os.linesep)
 
+
 def print_verbose(line):
     if verbose:
         print_stderr(line)
 
+
 def write_file(filename, data, mode='w', encoding='utf-8'):
     if 'b' in mode:
         encoding = None
     with open(filename, mode, encoding=encoding) as f:
         f.write(data)
 
+
 def read_file(filename, mode='r', encoding='utf-8'):
     if 'b' in mode:
         encoding = None
     with open(filename, mode, encoding=encoding) as f:
         return f.read()
 
+
 def run(cmd):
     global verbose
     if verbose:
@@ -111,6 +120,7 @@ def run(cmd):
     if os.system(cmd):
         raise EApp('failed command: %s' % cmd)
 
+
 def latex2img(infile, outfile, imgfmt, dpi, modified):
     '''
     Convert LaTeX input file infile to image file named outfile.
@@ -122,7 +132,7 @@ def latex2img(infile, outfile, imgfmt, dpi, modified):
     texfile = tempfile.mktemp(suffix='.tex', dir=os.path.dirname(outfile))
     basefile = os.path.splitext(texfile)[0]
     dvifile = basefile + '.dvi'
-    temps = [basefile + ext for ext in ('.tex','.dvi', '.aux', '.log')]
+    temps = [basefile + ext for ext in ('.tex', '.dvi', '.aux', '.log')]
     skip = False
     if infile == '-':
         tex = sys.stdin.read()
@@ -130,7 +140,7 @@ def latex2img(infile, outfile, imgfmt, dpi, modified):
             checksum = md5((tex + imgfmt + str(dpi)).encode('utf-8')).digest()
             md5_file = os.path.splitext(outfile)[0] + '.md5'
             if os.path.isfile(md5_file) and os.path.isfile(outfile) and \
-                    checksum == read_file(md5_file,'rb'):
+                    checksum == read_file(md5_file, 'rb'):
                 skip = True
     else:
         if not os.path.isfile(infile):
@@ -156,14 +166,14 @@ def latex2img(infile, outfile, imgfmt, dpi, modified):
             cmd += ' --no-fonts'
             cmd += ' --scale=1.4'
             cmd += ' --exact'
-            cmd += ' -o "%s" "%s"' % (outfile,dvifile)
+            cmd += ' -o "%s" "%s"' % (outfile, dvifile)
         else:
             # Convert DVI file to PNG.
             cmd = 'dvipng'
             if dpi:
                 cmd += ' -D %s' % dpi
             cmd += ' -T tight -x 1000 -z 9 -bg Transparent --truecolor'
-            cmd += ' -o "%s" "%s" ' % (outfile,dvifile)
+            cmd += ' -o "%s" "%s" ' % (outfile, dvifile)
         run(cmd)
     finally:
         os.chdir(saved_pwd)
@@ -175,21 +185,25 @@ def latex2img(infile, outfile, imgfmt, dpi, modified):
         print_verbose('writing: %s' % md5_file)
         write_file(md5_file, checksum, 'wb')
 
+
 def usage(msg=''):
     if msg:
         print_stderr(msg)
-    print_stderr('\n'
-                 'usage:\n'
-                 '    latex2img [options] INFILE\n'
-                 '\n'
-                 'options:\n'
-                 '    -D DPI\n'
-                 '    -o OUTFILE\n'
-                 '    -f FORMAT\n'
-                 '    -m\n'
-                 '    -v\n'
-                 '    --help\n'
-                 '    --version')
+    print_stderr(
+        '\n'
+        'usage:\n'
+        '    latex2img [options] INFILE\n'
+        '\n'
+        'options:\n'
+        '    -D DPI\n'
+        '    -o OUTFILE\n'
+        '    -f FORMAT\n'
+        '    -m\n'
+        '    -v\n'
+        '    --help\n'
+        '    --version'
+    )
+
 
 def main():
     # Process command line options.
@@ -199,19 +213,24 @@ def main():
     imgfmt = 'png'
     modified = False
     import getopt
-    opts,args = getopt.getopt(sys.argv[1:], 'D:o:mhvf:', ['help','version'])
-    for o,v in opts:
-        if o in ('--help','-h'):
+    opts, args = getopt.getopt(sys.argv[1:], 'D:o:mhvf:', ['help', 'version'])
+    for o, v in opts:
+        if o in ('--help', '-h'):
             print(__doc__)
             sys.exit(0)
-        if o =='--version':
+        if o == '--version':
             print(('latex2img version %s' % (VERSION,)))
             sys.exit(0)
-        if o == '-D': dpi = v
-        if o == '-o': outfile = v
-        if o == '-m': modified = True
-        if o == '-v': verbose = True
-        if o == '-f': imgfmt = v
+        if o == '-D':
+            dpi = v
+        if o == '-o':
+            outfile = v
+        if o == '-m':
+            modified = True
+        if o == '-v':
+            verbose = True
+        if o == '-f':
+            imgfmt = v
     if len(args) != 1:
         usage()
         sys.exit(1)
@@ -219,7 +238,7 @@ def main():
     if dpi and not dpi.isdigit():
         usage('invalid DPI')
         sys.exit(1)
-    if not imgfmt in {'png', 'svg'}:
+    if imgfmt not in {'png', 'svg'}:
         usage('Invalid image format. Valid values are "png" or "svg".')
         sys.exit(1)
     if outfile is None:
@@ -233,6 +252,7 @@ def main():
     if infile == '-':
         sys.stdout.write(' ')
 
+
 if __name__ == "__main__":
     try:
         main()
diff --git a/filters/music/music2png.py b/filters/music/music2png.py
index 185137c..4458108 100755
--- a/filters/music/music2png.py
+++ b/filters/music/music2png.py
@@ -50,7 +50,9 @@ COPYING
     granted under the terms of the GNU General Public License (GPL).
 '''
 
-import os, sys, tempfile
+import os
+import sys
+import tempfile
 from hashlib import md5
 
 VERSION = '0.1.2'
@@ -58,27 +60,34 @@ VERSION = '0.1.2'
 # Globals.
 verbose = False
 
-class EApp(Exception): pass     # Application specific exception.
+
+class EApp(Exception):
+    pass     # Application specific exception.
+
 
 def print_stderr(line):
     sys.stderr.write(line + os.linesep)
 
+
 def print_verbose(line):
     if verbose:
         print_stderr(line)
 
+
 def write_file(filename, data, mode='w', encoding='utf-8'):
     if 'b' in mode:
         encoding = None
     with open(filename, mode, encoding=encoding) as f:
         f.write(data)
 
+
 def read_file(filename, mode='r', encoding='utf-8'):
     if 'b' in mode:
         encoding = None
     with open(filename, mode, encoding=encoding) as f:
         return f.read()
 
+
 def run(cmd):
     global verbose
     if not verbose:
@@ -87,6 +96,7 @@ def run(cmd):
     if os.system(cmd):
         raise EApp('failed command: %s' % cmd)
 
+
 def music2png(format, infile, outfile, modified):
     '''Convert ABC notation in file infile to cropped PNG file named outfile.'''
     outfile = os.path.abspath(outfile)
@@ -102,7 +112,7 @@ def music2png(format, infile, outfile, modified):
         filename = os.path.splitext(outfile)[0] + '.md5'
         if modified:
             if os.path.isfile(filename) and os.path.isfile(outfile) and \
-                    checksum == read_file(filename,'rb'):
+                    checksum == read_file(filename, 'rb'):
                 skip = True
             else:
                 write_file(filename, checksum, 'wb')
@@ -122,7 +132,7 @@ def music2png(format, infile, outfile, modified):
         else:
             format = 'abc'
     # Write temporary source file.
-    write_file('%s.%s' % (basefile,format), source)
+    write_file('%s.%s' % (basefile, format), source)
     abc = basefile + '.abc'
     ly = basefile + '.ly'
     png = basefile + '.png'
@@ -130,8 +140,8 @@ def music2png(format, infile, outfile, modified):
     os.chdir(outdir)
     try:
         if format == 'abc':
-            run('abc2ly -o "%s" "%s"' % (ly,abc))
-        run('lilypond --png -o "%s" "%s"' % (basefile,ly))
+            run('abc2ly -o "%s" "%s"' % (ly, abc))
+        run('lilypond --png -o "%s" "%s"' % (basefile, ly))
         os.rename(png, outfile)
     finally:
         os.chdir(saved_pwd)
@@ -144,20 +154,24 @@ def music2png(format, infile, outfile, modified):
             print_verbose('deleting: %s' % f)
             os.remove(f)
 
+
 def usage(msg=''):
     if msg:
         print_stderr(msg)
-    print_stderr('\n'
-                 'usage:\n'
-                 '    music2png [options] INFILE\n'
-                 '\n'
-                 'options:\n'
-                 '    -f FORMAT\n'
-                 '    -o OUTFILE\n'
-                 '    -m\n'
-                 '    -v\n'
-                 '    --help\n'
-                 '    --version')
+    print_stderr(
+        '\n'
+        'usage:\n'
+        '    music2png [options] INFILE\n'
+        '\n'
+        'options:\n'
+        '    -f FORMAT\n'
+        '    -o OUTFILE\n'
+        '    -m\n'
+        '    -v\n'
+        '    --help\n'
+        '    --version'
+    )
+
 
 def main():
     # Process command line options.
@@ -166,18 +180,22 @@ def main():
     outfile = None
     modified = False
     import getopt
-    opts,args = getopt.getopt(sys.argv[1:], 'f:o:mhv', ['help','version'])
-    for o,v in opts:
-        if o in ('--help','-h'):
+    opts, args = getopt.getopt(sys.argv[1:], 'f:o:mhv', ['help', 'version'])
+    for o, v in opts:
+        if o in ('--help', '-h'):
             print(__doc__)
             sys.exit(0)
-        if o =='--version':
+        if o == '--version':
             print(('music2png version %s' % (VERSION,)))
             sys.exit(0)
-        if o == '-f': format = v
-        if o == '-o': outfile = v
-        if o == '-m': modified = True
-        if o == '-v': verbose = True
+        if o == '-f':
+            format = v
+        if o == '-o':
+            outfile = v
+        if o == '-m':
+            modified = True
+        if o == '-v':
+            verbose = True
     if len(args) != 1:
         usage()
         sys.exit(1)
@@ -196,6 +214,7 @@ def main():
     if infile == '-':
         sys.stdout.write(' ')
 
+
 if __name__ == "__main__":
     try:
         main()
diff --git a/filters/unwraplatex.py b/filters/unwraplatex.py
index 57c84cf..05a7581 100755
--- a/filters/unwraplatex.py
+++ b/filters/unwraplatex.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-'''
+"""
 NAME
     unwraplatex - Removes delimiters from LaTeX source text
 
@@ -8,15 +8,15 @@ SYNOPSIS
 
 DESCRIPTION
     This filter reads LaTeX source text from STDIN and removes the
-    surrounding \[ and \] delimiters.
-'''
+    surrounding \\[ and \\] delimiters.
+"""
 
 import re
 import sys
 
 sys.stdout.write(
     re.sub(
-        "(?s)\A(?:\\\\\[\s*)?(.*?)(?:\\\\\])?\Z", "\\1",
+        r"(?s)\A(?:\\\[\s*)?(.*?)(?:\\\])?\Z", "\\1",
         sys.stdin.read().rstrip()
     )
 )
diff --git a/tests/data/barchart.py b/tests/data/barchart.py
index e2edf74..3472cde 100644
--- a/tests/data/barchart.py
+++ b/tests/data/barchart.py
@@ -1,2 +1,4 @@
-print("No barchart to avoid depending on Pychart for the tests.\n"
-      "See also: http://asciidoc.org/faq.html#_is_it_possible_to_include_charts_in_asciidoc_documents")
+print(
+      "No barchart to avoid depending on Pychart for the tests.\n"
+      "See also: http://asciidoc.org/faq.html#_is_it_possible_to_include_charts_in_asciidoc_documents"  # noqa: E501
+)
diff --git a/tests/testasciidoc.py b/tests/testasciidoc.py
index 6c3ffa5..85f34a4 100755
--- a/tests/testasciidoc.py
+++ b/tests/testasciidoc.py
@@ -300,7 +300,7 @@ class AsciiDocTests(object):
             first = True
             while not lines.eol():
                 s = lines.read_until(r'^%+$')
-                s = [l for l in s if l]    # Drop blank lines.
+                s = [line for line in s if len(line) > 0]    # Drop blank lines.
                 # Must be at least one non-blank line in addition to delimiter.
                 if len(s) > 1:
                     # Optional globals precede all tests.