Fix coding style errors reported by make check

These were introduced in e6488e6c0fd0416c54ecff1dd682f0ae8aa4c6fb and
e6488e6c0fd0416c54ecff1dd682f0ae8aa4c6fb:

    src/dfeet/introspection_helper.py:9:1: E302 expected 2 blank lines, found 1
    src/dfeet/introspection_helper.py:14:100: E501 line too long (107 > 99 characters)
    src/dfeet/introspection_helper.py:17:1: E302 expected 2 blank lines, found 1
    src/dfeet/introspection_helper.py:20:1: E302 expected 2 blank lines, found 1
    src/dfeet/introspection_helper.py:23:1: E302 expected 2 blank lines, found 1

1 files changed, 9 insertions, 1 deletions

diff --git a/src/dfeet/introspection_helper.py b/src/dfeet/introspection_helper.py
index d927d96..b718c1a 100644
--- a/src/dfeet/introspection_helper.py
+++ b/src/dfeet/introspection_helper.py
@@ -6,20 +6,28 @@ from dfeet import dbus_utils
 _style_context = None
 _fg_color = "#000000"
 
+
 def fg_color():
     global _style_context, _fg_color
     if _style_context is None:
         _style_context = Gtk.StyleContext()
         color = _style_context.get_color(Gtk.StateFlags.NORMAL)
-        _fg_color = "#%02x%02x%02x" % (int(color.red) * 255, int(color.green) * 255, int(color.blue) * 255)
+        _fg_color = "#%02x%02x%02x" % (
+            int(color.red) * 255,
+            int(color.green) * 255,
+            int(color.blue) * 255,
+        )
     return _fg_color
 
+
 def args_signature_markup(arg_signature):
     return '<small><span foreground="#2E8B57">%s</span></small>' % (arg_signature)
 
+
 def args_name_markup(arg_name):
     return '<small><span foreground="%s">%s</span></small>' % (fg_color(), arg_name)
 
+
 class DBusNode(GObject.GObject):
     """object to represent a DBus Node (object path)"""
     def __init__(self, name, object_path, node_info):