whitespace removal

1 files changed, 130 insertions, 130 deletions

diff --git a/alembic/environment.py b/alembic/environment.py
index 9db519f..a402bde 100644
--- a/alembic/environment.py
+++ b/alembic/environment.py
@@ -6,30 +6,30 @@ from contextlib import contextmanager
 
 class EnvironmentContext(object):
     """Represent the state made available to an ``env.py`` script.
-    
+
     :class:`.EnvironmentContext` is normally instantiated
     by the commands present in the :mod:`alembic.command`
     module.  From within an ``env.py`` script, the current
-    :class:`.EnvironmentContext` is available via the 
+    :class:`.EnvironmentContext` is available via the
     ``alembic.context`` datamember.
-    
+
     :class:`.EnvironmentContext` is also a Python context
     manager, that is, is intended to be used using the
     ``with:`` statement.  A typical use of :class:`.EnvironmentContext`::
 
         from alembic.config import Config
         from alembic.script import ScriptDirectory
-        
+
         config = Config()
         config.set_main_option("script_location", "myapp:migrations")
         script = ScriptDirectory.from_config(config)
-        
+
         def my_function(rev, context):
             '''do something with revision "rev", which
-            will be the current database revision, 
+            will be the current database revision,
             and "context", which is the MigrationContext
             that the env.py will create'''
-            
+
         with EnvironmentContext(
             config,
             script,
@@ -40,49 +40,49 @@ class EnvironmentContext(object):
             tag = "sometag"
         ):
             script.run_env()
-    
+
     The above script will invoke the ``env.py`` script
     within the migration environment.  If and when ``env.py``
     calls :meth:`.MigrationContext.run_migrations`, the
-    ``my_function()`` function above will be called 
+    ``my_function()`` function above will be called
     by the :class:`.MigrationContext`, given the context
     itself as well as the current revision in the database.
-    
+
     .. note::
 
         For most API usages other than full blown
         invocation of migration scripts, the :class:`.MigrationContext`
         and :class:`.ScriptDirectory` objects can be created and
-        used directly.  The :class:`.EnvironmentContext` object 
+        used directly.  The :class:`.EnvironmentContext` object
         is *only* needed when you need to actually invoke the
         ``env.py`` module present in the migration environment.
-    
+
     """
 
     _migration_context = None
     _default_opts = None
 
     config = None
-    """An instance of :class:`.Config` representing the 
+    """An instance of :class:`.Config` representing the
     configuration file contents as well as other variables
     set programmatically within it."""
 
     script = None
     """An instance of :class:`.ScriptDirectory` which provides
-    programmatic access to version files within the ``versions/`` 
+    programmatic access to version files within the ``versions/``
     directory.
-    
+
     """
 
     def __init__(self, config, script, **kw):
         """Construct a new :class:`.EnvironmentContext`.
-        
+
         :param config: a :class:`.Config` instance.
         :param script: a :class:`.ScriptDirectory` instance.
         :param \**kw: keyword options that will be ultimately
          passed along to the :class:`.MigrationContext` when
          :meth:`.EnvironmentContext.configure` is called.
-         
+
         """
         self.config = config
         self.script = script
@@ -91,13 +91,13 @@ class EnvironmentContext(object):
             self.context_opts.update(self._default_opts)
 
     def __enter__(self):
-        """Establish a context which provides a 
+        """Establish a context which provides a
         :class:`.EnvironmentContext` object to
         env.py scripts.
-    
+
         The :class:`.EnvironmentContext` will
         be made available as ``from alembic import context``.
-    
+
         """
         alembic.context._install_proxy(self)
         return self
@@ -107,13 +107,13 @@ class EnvironmentContext(object):
         alembic.op._remove_proxy()
 
     def is_offline_mode(self):
-        """Return True if the current migrations environment 
+        """Return True if the current migrations environment
         is running in "offline mode".
 
-        This is ``True`` or ``False`` depending 
+        This is ``True`` or ``False`` depending
         on the the ``--sql`` flag passed.
 
-        This function does not require that the :class:`.MigrationContext` 
+        This function does not require that the :class:`.MigrationContext`
         has been configured.
 
         """
@@ -123,11 +123,11 @@ class EnvironmentContext(object):
         """Return True if the context is configured to expect a
         transactional DDL capable backend.
 
-        This defaults to the type of database in use, and 
+        This defaults to the type of database in use, and
         can be overridden by the ``transactional_ddl`` argument
         to :meth:`.configure`
 
-        This function requires that a :class:`.MigrationContext` 
+        This function requires that a :class:`.MigrationContext`
         has first been made available via :meth:`.configure`.
 
         """
@@ -139,7 +139,7 @@ class EnvironmentContext(object):
     def get_head_revision(self):
         """Return the hex identifier of the 'head' revision.
 
-        This function does not require that the :class:`.MigrationContext` 
+        This function does not require that the :class:`.MigrationContext`
         has been configured.
 
         """
@@ -153,7 +153,7 @@ class EnvironmentContext(object):
         Returns ``None`` if no value is available
         or was configured.
 
-        This function does not require that the :class:`.MigrationContext` 
+        This function does not require that the :class:`.MigrationContext`
         has been configured.
 
         """
@@ -170,14 +170,14 @@ class EnvironmentContext(object):
     def get_revision_argument(self):
         """Get the 'destination' revision argument.
 
-        This is typically the argument passed to the 
+        This is typically the argument passed to the
         ``upgrade`` or ``downgrade`` command.
 
-        If it was specified as ``head``, the actual 
+        If it was specified as ``head``, the actual
         version number is returned; if specified
         as ``base``, ``None`` is returned.
 
-        This function does not require that the :class:`.MigrationContext` 
+        This function does not require that the :class:`.MigrationContext`
         has been configured.
 
         """
@@ -188,11 +188,11 @@ class EnvironmentContext(object):
         """Return the value passed for the ``--tag`` argument, if any.
 
         The ``--tag`` argument is not used directly by Alembic,
-        but is available for custom ``env.py`` configurations that 
+        but is available for custom ``env.py`` configurations that
         wish to use it; particularly for offline generation scripts
         that wish to generate tagged filenames.
 
-        This function does not require that the :class:`.MigrationContext` 
+        This function does not require that the :class:`.MigrationContext`
         has been configured.
 
         """
@@ -217,62 +217,62 @@ class EnvironmentContext(object):
             **kw
         ):
         """Configure a :class:`.MigrationContext` within this
-        :class:`.EnvironmentContext` which will provide database 
-        connectivity and other configuration to a series of 
+        :class:`.EnvironmentContext` which will provide database
+        connectivity and other configuration to a series of
         migration scripts.
-        
-        Many methods on :class:`.EnvironmentContext` require that 
+
+        Many methods on :class:`.EnvironmentContext` require that
         this method has been called in order to function, as they
         ultimately need to have database access or at least access
         to the dialect in use.  Those which do are documented as such.
-        
+
         The important thing needed by :meth:`.configure` is a
-        means to determine what kind of database dialect is in use.  
+        means to determine what kind of database dialect is in use.
         An actual connection to that database is needed only if
-        the :class:`.MigrationContext` is to be used in 
+        the :class:`.MigrationContext` is to be used in
         "online" mode.
 
         If the :meth:`.is_offline_mode` function returns ``True``,
         then no connection is needed here.  Otherwise, the
-        ``connection`` parameter should be present as an 
+        ``connection`` parameter should be present as an
         instance of :class:`sqlalchemy.engine.base.Connection`.
 
         This function is typically called from the ``env.py``
         script within a migration environment.  It can be called
-        multiple times for an invocation.  The most recent 
+        multiple times for an invocation.  The most recent
         :class:`~sqlalchemy.engine.base.Connection`
         for which it was called is the one that will be operated upon
         by the next call to :meth:`.run_migrations`.
 
         General parameters:
-    
-        :param connection: a :class:`~sqlalchemy.engine.base.Connection` 
+
+        :param connection: a :class:`~sqlalchemy.engine.base.Connection`
          to use
-         for SQL execution in "online" mode.  When present, is also 
+         for SQL execution in "online" mode.  When present, is also
          used to determine the type of dialect in use.
-        :param url: a string database url, or a 
+        :param url: a string database url, or a
          :class:`sqlalchemy.engine.url.URL` object.
-         The type of dialect to be used will be derived from this if 
+         The type of dialect to be used will be derived from this if
          ``connection`` is not passed.
-        :param dialect_name: string name of a dialect, such as 
+        :param dialect_name: string name of a dialect, such as
          "postgresql", "mssql", etc.
-         The type of dialect to be used will be derived from this if 
+         The type of dialect to be used will be derived from this if
          ``connection`` and ``url`` are not passed.
-        :param transactional_ddl: Force the usage of "transactional" 
+        :param transactional_ddl: Force the usage of "transactional"
          DDL on or off;
-         this otherwise defaults to whether or not the dialect in 
+         this otherwise defaults to whether or not the dialect in
          use supports it.
-        :param output_buffer: a file-like object that will be used 
+        :param output_buffer: a file-like object that will be used
          for textual output
-         when the ``--sql`` option is used to generate SQL scripts.  
+         when the ``--sql`` option is used to generate SQL scripts.
          Defaults to
-         ``sys.stdout`` if not passed here and also not present on 
+         ``sys.stdout`` if not passed here and also not present on
          the :class:`.Config`
-         object.  The value here overrides that of the :class:`.Config` 
+         object.  The value here overrides that of the :class:`.Config`
          object.
-        :param starting_rev: Override the "starting revision" argument 
+        :param starting_rev: Override the "starting revision" argument
          when using ``--sql`` mode.
-        :param tag: a string tag for usage by custom ``env.py`` scripts.  
+        :param tag: a string tag for usage by custom ``env.py`` scripts.
          Set via the ``--tag`` option, can be overridden here.
         :param template_args: dictionary of template arguments which
          will be added to the template argument environment when
@@ -283,60 +283,60 @@ class EnvironmentContext(object):
         :param version_table: The name of the Alembic version table.
          The default is ``'alembic_version'``.
 
-        Parameters specific to the autogenerate feature, when 
+        Parameters specific to the autogenerate feature, when
         ``alembic revision`` is run with the ``--autogenerate`` feature:
-    
-        :param target_metadata: a :class:`sqlalchemy.schema.MetaData` 
+
+        :param target_metadata: a :class:`sqlalchemy.schema.MetaData`
          object that
-         will be consulted during autogeneration.  The tables present 
+         will be consulted during autogeneration.  The tables present
          will be compared against
-         what is locally available on the target 
+         what is locally available on the target
          :class:`~sqlalchemy.engine.base.Connection`
          to produce candidate upgrade/downgrade operations.
-     
-        :param compare_type: Indicates type comparison behavior during 
+
+        :param compare_type: Indicates type comparison behavior during
          an autogenerate
-         operation.  Defaults to ``False`` which disables type 
-         comparison.  Set to 
-         ``True`` to turn on default type comparison, which has varied 
+         operation.  Defaults to ``False`` which disables type
+         comparison.  Set to
+         ``True`` to turn on default type comparison, which has varied
          accuracy depending on backend.
-     
-         To customize type comparison behavior, a callable may be 
+
+         To customize type comparison behavior, a callable may be
          specified which
-         can filter type comparisons during an autogenerate operation.   
+         can filter type comparisons during an autogenerate operation.
          The format of this callable is::
-     
-            def my_compare_type(context, inspected_column, 
+
+            def my_compare_type(context, inspected_column,
                         metadata_column, inspected_type, metadata_type):
                 # return True if the types are different,
                 # False if not, or None to allow the default implementation
                 # to compare these types
                 pass
-    
+
          ``inspected_column`` is a dictionary structure as returned by
          :meth:`sqlalchemy.engine.reflection.Inspector.get_columns`, whereas
          ``metadata_column`` is a :class:`sqlalchemy.schema.Column` from
          the local model environment.
-     
-         A return value of ``None`` indicates to allow default type 
+
+         A return value of ``None`` indicates to allow default type
          comparison to proceed.
 
-        :param compare_server_default: Indicates server default comparison 
-         behavior during 
-         an autogenerate operation.  Defaults to ``False`` which disables 
-         server default 
-         comparison.  Set to  ``True`` to turn on server default comparison, 
-         which has 
+        :param compare_server_default: Indicates server default comparison
+         behavior during
+         an autogenerate operation.  Defaults to ``False`` which disables
+         server default
+         comparison.  Set to  ``True`` to turn on server default comparison,
+         which has
          varied accuracy depending on backend.
-    
-         To customize server default comparison behavior, a callable may 
+
+         To customize server default comparison behavior, a callable may
          be specified
-         which can filter server default comparisons during an 
+         which can filter server default comparisons during an
          autogenerate operation.
-         defaults during an autogenerate operation.   The format of this 
+         defaults during an autogenerate operation.   The format of this
          callable is::
-     
-            def my_compare_server_default(context, inspected_column, 
+
+            def my_compare_server_default(context, inspected_column,
                         metadata_column, inspected_default, metadata_default,
                         rendered_metadata_default):
                 # return True if the defaults are different,
@@ -349,47 +349,47 @@ class EnvironmentContext(object):
          ``metadata_column`` is a :class:`sqlalchemy.schema.Column` from
          the local model environment.
 
-         A return value of ``None`` indicates to allow default server default 
-         comparison 
-         to proceed.  Note that some backends such as Postgresql actually 
+         A return value of ``None`` indicates to allow default server default
+         comparison
+         to proceed.  Note that some backends such as Postgresql actually
          execute
          the two defaults on the database side to compare for equivalence.
 
-        :param upgrade_token: When autogenerate completes, the text of the 
-         candidate upgrade operations will be present in this template 
-         variable when ``script.py.mako`` is rendered.  Defaults to 
+        :param upgrade_token: When autogenerate completes, the text of the
+         candidate upgrade operations will be present in this template
+         variable when ``script.py.mako`` is rendered.  Defaults to
          ``upgrades``.
-        :param downgrade_token: When autogenerate completes, the text of the 
+        :param downgrade_token: When autogenerate completes, the text of the
          candidate downgrade operations will be present in this
-         template variable when ``script.py.mako`` is rendered.  Defaults to 
+         template variable when ``script.py.mako`` is rendered.  Defaults to
          ``downgrades``.
 
-        :param alembic_module_prefix: When autogenerate refers to Alembic 
+        :param alembic_module_prefix: When autogenerate refers to Alembic
          :mod:`alembic.operations` constructs, this prefix will be used
          (i.e. ``op.create_table``)  Defaults to "``op.``".
-         Can be ``None`` to indicate no prefix.  
-     
-        :param sqlalchemy_module_prefix: When autogenerate refers to 
-         SQLAlchemy 
-         :class:`~sqlalchemy.schema.Column` or type classes, this prefix 
+         Can be ``None`` to indicate no prefix.
+
+        :param sqlalchemy_module_prefix: When autogenerate refers to
+         SQLAlchemy
+         :class:`~sqlalchemy.schema.Column` or type classes, this prefix
          will be used
          (i.e. ``sa.Column("somename", sa.Integer)``)  Defaults to "``sa.``".
-         Can be ``None`` to indicate no prefix.  
+         Can be ``None`` to indicate no prefix.
          Note that when dialect-specific types are rendered, autogenerate
-         will render them using the dialect module name, i.e. ``mssql.BIT()``, 
+         will render them using the dialect module name, i.e. ``mssql.BIT()``,
          ``postgresql.UUID()``.
-     
+
         Parameters specific to individual backends:
-    
-        :param mssql_batch_separator: The "batch separator" which will 
-         be placed between each statement when generating offline SQL Server 
-         migrations.  Defaults to ``GO``.  Note this is in addition to the 
-         customary semicolon ``;`` at the end of each statement; SQL Server 
-         considers the "batch separator" to denote the end of an 
-         individual statement execution, and cannot group certain 
+
+        :param mssql_batch_separator: The "batch separator" which will
+         be placed between each statement when generating offline SQL Server
+         migrations.  Defaults to ``GO``.  Note this is in addition to the
+         customary semicolon ``;`` at the end of each statement; SQL Server
+         considers the "batch separator" to denote the end of an
+         individual statement execution, and cannot group certain
          dependent operations in one step.
         :param oracle_batch_separator: The "batch separator" which will
-         be placed between each statement when generating offline 
+         be placed between each statement when generating offline
          Oracle migrations.  Defaults to ``/``.  Oracle doesn't add a
          semicolon between statements like most other backends.
 
@@ -427,13 +427,13 @@ class EnvironmentContext(object):
         )
 
     def run_migrations(self, **kw):
-        """Run migrations as determined by the current command line 
+        """Run migrations as determined by the current command line
         configuration
-        as well as versioning information present (or not) in the current 
+        as well as versioning information present (or not) in the current
         database connection (if one is present).
 
         The function accepts optional ``**kw`` arguments.   If these are
-        passed, they are sent directly to the ``upgrade()`` and 
+        passed, they are sent directly to the ``upgrade()`` and
         ``downgrade()``
         functions within each target revision file.   By modifying the
         ``script.py.mako`` file so that the ``upgrade()`` and ``downgrade()``
@@ -442,7 +442,7 @@ class EnvironmentContext(object):
         database in use, can be passed from a custom ``env.py`` script
         to the migration functions.
 
-        This function requires that a :class:`.MigrationContext` has 
+        This function requires that a :class:`.MigrationContext` has
         first been made available via :meth:`.configure`.
 
         """
@@ -457,39 +457,39 @@ class EnvironmentContext(object):
         function's documentation for full detail including
         caveats and limitations.
 
-        This function requires that a :class:`.MigrationContext` has 
+        This function requires that a :class:`.MigrationContext` has
         first been made available via :meth:`.configure`.
 
         """
-        self.get_context().execute(sql, 
+        self.get_context().execute(sql,
                 execution_options=execution_options)
 
     def static_output(self, text):
         """Emit text directly to the "offline" SQL stream.
-    
-        Typically this is for emitting comments that 
+
+        Typically this is for emitting comments that
         start with --.  The statement is not treated
         as a SQL execution, no ; or batch separator
         is added, etc.
-    
+
         """
         self.get_context().impl.static_output(text)
 
     def begin_transaction(self):
-        """Return a context manager that will 
+        """Return a context manager that will
         enclose an operation within a "transaction",
         as defined by the environment's offline
         and transactional DDL settings.
 
         e.g.::
-    
+
             with context.begin_transaction():
                 context.run_migrations()
-    
+
         :meth:`.begin_transaction` is intended to
-        "do the right thing" regardless of 
+        "do the right thing" regardless of
         calling context:
-    
+
         * If :meth:`.is_transactional_ddl` is ``False``,
           returns a "do nothing" context manager
           which otherwise produces no transactional
@@ -510,8 +510,8 @@ class EnvironmentContext(object):
           transaction and is itself a context manager,
           which will roll back if an exception
           is raised.
-    
-        Note that a custom ``env.py`` script which 
+
+        Note that a custom ``env.py`` script which
         has more specific transactional needs can of course
         manipulate the :class:`~sqlalchemy.engine.base.Connection`
         directly to produce transactional state in "online"
@@ -536,7 +536,7 @@ class EnvironmentContext(object):
     def get_context(self):
         """Return the current :class:`.MigrationContext` object.
 
-        If :meth:`.EnvironmentContext.configure` has not been 
+        If :meth:`.EnvironmentContext.configure` has not been
         called yet, raises an exception.
 
         """
@@ -548,11 +548,11 @@ class EnvironmentContext(object):
     def get_bind(self):
         """Return the current 'bind'.
 
-        In "online" mode, this is the 
+        In "online" mode, this is the
         :class:`sqlalchemy.engine.base.Connection` currently being used
         to emit SQL to the database.
 
-        This function requires that a :class:`.MigrationContext` 
+        This function requires that a :class:`.MigrationContext`
         has first been made available via :meth:`.configure`.
 
         """