diff --git a/migrate/versioning/api.py b/migrate/versioning/api.py
index 12e0d75..9cd5253 100644
--- a/migrate/versioning/api.py
+++ b/migrate/versioning/api.py
@@ -14,11 +14,13 @@
 
 import sys
 import inspect
-from sqlalchemy import create_engine
-from migrate.versioning import exceptions, repository, schema, version
-import script as script_ #command name conflict
 
-__all__=[
+from sqlalchemy import create_engine
+
+from migrate.versioning import (exceptions, repository, schema, version,
+    script as script_) # command name conflict
+
+__all__ = [
 'help',
 'create',
 'script',
@@ -73,7 +75,7 @@ def create(repository, name, **opts):
     databases.
     """
     try:
-        rep=cls_repository.create(repository, name, **opts)
+        rep = cls_repository.create(repository, name, **opts)
     except exceptions.PathFoundError, e:
         raise exceptions.KnownError("The path %s already exists" % e.args[0])
 
@@ -93,7 +95,7 @@ def script(description, repository=None, **opts):
         repos = cls_repository(repository)
         repos.create_script(description, **opts)
     except exceptions.PathFoundError, e:
-        raise exceptions.KnownError("The path %s already exists"%e.args[0])
+        raise exceptions.KnownError("The path %s already exists" % e.args[0])
 
 
 def script_sql(database, repository=None, **opts):
@@ -113,7 +115,7 @@ def script_sql(database, repository=None, **opts):
         repos = cls_repository(repository)
         repos.create_script_sql(database, **opts)
     except exceptions.PathFoundError, e:
-        raise exceptions.KnownError("The path %s already exists"%e.args[0])
+        raise exceptions.KnownError("The path %s already exists" % e.args[0])
 
 
 def test(repository, url=None, **opts):
@@ -124,8 +126,8 @@ def test(repository, url=None, **opts):
     bad state. You should therefore better run the test on a copy of
     your database.
     """
-    engine=create_engine(url)
-    repos=cls_repository(repository)
+    engine = create_engine(url)
+    repos = cls_repository(repository)
     script = repos.version(None).script()
     # Upgrade
     print "Upgrading...",
@@ -151,7 +153,7 @@ def version(repository, **opts):
 
     Display the latest version available in a repository.
     """
-    repos=cls_repository(repository)
+    repos = cls_repository(repository)
     return repos.latest
 
 
@@ -164,12 +166,12 @@ def source(version, dest=None, repository=None, **opts):
     """
     if repository is None:
         raise exceptions.UsageError("A repository must be specified")
-    repos=cls_repository(repository)
-    ret=repos.version(version).script().source()
+    repos = cls_repository(repository)
+    ret = repos.version(version).script().source()
     if dest is not None:
-        dest=open(dest, 'w')
+        dest = open(dest, 'w')
         dest.write(ret)
-        ret=None
+        ret = None
     return ret
 
 
diff --git a/migrate/versioning/cfgparse.py b/migrate/versioning/cfgparse.py
index e8f9a85..b2660bd 100644
--- a/migrate/versioning/cfgparse.py
+++ b/migrate/versioning/cfgparse.py
@@ -2,9 +2,10 @@
    Configuration parser module.
 """
 
+from ConfigParser import ConfigParser
+
 from migrate.versioning.base import *
 from migrate.versioning import pathed
-from ConfigParser import ConfigParser
 
 
 class Parser(ConfigParser):
diff --git a/migrate/versioning/exceptions.py b/migrate/versioning/exceptions.py
index 6cbf309..2a19741 100644
--- a/migrate/versioning/exceptions.py
+++ b/migrate/versioning/exceptions.py
@@ -56,11 +56,12 @@ class LogSqlError(Error):
         self.entry = entry
 
     def __str__(self):
-        ret = "SQL error in statement: \n%s\n"%(str(self.entry))
-        ret += "Traceback from change script:\n"
-        ret += ''.join(traceback.format_list(self.entry.traceback))
-        ret += str(self.sqlerror)
-        return ret
+        """SQL error in statement:
+        %s
+        Traceback from change script:
+        %s%s""" % (self.entry,
+            ''.join(traceback.format_list(self.entry.traceback)),
+            self.sqlerror)
 
 
 class PathError(Error):
diff --git a/migrate/versioning/genmodel.py b/migrate/versioning/genmodel.py
index b62cb65..7d03fa7 100644
--- a/migrate/versioning/genmodel.py
+++ b/migrate/versioning/genmodel.py
@@ -7,6 +7,7 @@
 """
 
 import sys
+
 import migrate
 import sqlalchemy
 
diff --git a/migrate/versioning/migrate_repository.py b/migrate/versioning/migrate_repository.py
index acc728e..27c4d35 100644
--- a/migrate/versioning/migrate_repository.py
+++ b/migrate/versioning/migrate_repository.py
@@ -5,7 +5,6 @@
 """
 
 import os
-import os.path
 import sys
 
 
diff --git a/migrate/versioning/pathed.py b/migrate/versioning/pathed.py
index a316d90..1901e4f 100644
--- a/migrate/versioning/pathed.py
+++ b/migrate/versioning/pathed.py
@@ -2,11 +2,12 @@
    A path/directory class.
 """
 
+import os
+import shutil
+
 from migrate.versioning.base import *
 from migrate.versioning.util import KeyedInstance
 from migrate.versioning import exceptions
-import os
-import shutil
 
 
 class Pathed(KeyedInstance):
@@ -16,21 +17,21 @@ class Pathed(KeyedInstance):
     Only one instance of this class may exist for a particular file;
     __new__ will return an existing instance if possible
     """
-    parent=None
+    parent = None
 
     @classmethod
     def _key(cls, path):
         return str(path)
 
     def __init__(self, path):
-        self.path=path
+        self.path = path
         if self.__class__.parent is not None:
             self._init_parent(path)
 
     def _init_parent(self, path):
         """Try to initialize this object's parent, if it has one"""
-        parent_path=self.__class__._parent_path(path)
-        self.parent=self.__class__.parent(parent_path)
+        parent_path = self.__class__._parent_path(path)
+        self.parent = self.__class__.parent(parent_path)
         log.info("Getting parent %r:%r" % (self.__class__.parent, parent_path))
         self.parent._init_child(path, self)
 
diff --git a/migrate/versioning/repository.py b/migrate/versioning/repository.py
index b2d9ef6..47c056c 100644
--- a/migrate/versioning/repository.py
+++ b/migrate/versioning/repository.py
@@ -1,13 +1,14 @@
 """
    SQLAlchemy migrate repository management.
 """
-from pkg_resources import resource_string, resource_filename
 import os
 import shutil
 import string
-from migrate.versioning.base import *
-from migrate.versioning.template import template
+from pkg_resources import resource_string, resource_filename
+
 from migrate.versioning import exceptions, script, version, pathed, cfgparse
+from migrate.versioning.template import template
+from migrate.versioning.base import *
 
 
 class Changeset(dict):
@@ -61,9 +62,9 @@ class Changeset(dict):
 class Repository(pathed.Pathed):
     """A project's change script repository"""
     # Configuration file, inside repository
-    _config='migrate.cfg'
+    _config = 'migrate.cfg'
     # Version information, inside repository
-    _versions='versions'
+    _versions = 'versions'
 
     def __init__(self, path):
         log.info('Loading repository %s...' % path)
@@ -177,7 +178,7 @@ def manage(file, **opts):
     """Create a project management script"""
     pkg, rsrc = template.manage(as_pkg=True)
     tmpl = resource_string(pkg, rsrc)
-    vars = ",".join(["%s='%s'"%vars for vars in opts.iteritems()])
+    vars = ",".join(["%s='%s'" % vars for vars in opts.iteritems()])
     result = tmpl%dict(defaults=vars)
 
     fd = open(file, 'w')
diff --git a/migrate/versioning/schema.py b/migrate/versioning/schema.py
index 26a65c3..4b39d57 100644
--- a/migrate/versioning/schema.py
+++ b/migrate/versioning/schema.py
@@ -1,21 +1,22 @@
 """
    Database schema version management.
 """
-from sqlalchemy import Table, Column, MetaData, String, Text, Integer, \
-    create_engine
+from sqlalchemy import (Table, Column, MetaData, String, Text, Integer,
+    create_engine)
 from sqlalchemy.sql import and_
 from sqlalchemy import exceptions as sa_exceptions
+
+from migrate.versioning import exceptions, genmodel, schemadiff
 from migrate.versioning.repository import Repository
 from migrate.versioning.util import loadModel
 from migrate.versioning.version import VerNum
-from migrate.versioning import exceptions, genmodel, schemadiff
 
 
 class ControlledSchema(object):
     """A database under version control"""
 
     def __init__(self, engine, repository):
-        if type(repository) is str:
+        if isinstance(repository, str):
             repository=Repository(repository)
         self.engine = engine
         self.repository = repository
@@ -76,7 +77,7 @@ class ControlledSchema(object):
         :return: valid version number
         """
         if version is None:
-            version=0
+            version = 0
         try:
             version = VerNum(version) # raises valueerror
             if version < 0 or version > repository.latest:
diff --git a/migrate/versioning/shell.py b/migrate/versioning/shell.py
index 48b30c3..116a72d 100644
--- a/migrate/versioning/shell.py
+++ b/migrate/versioning/shell.py
@@ -14,6 +14,7 @@ alias = dict(
     dbv=api.db_version,
     v=api.version,
 )
+
 def alias_setup():
     global alias
     for key,val in alias.iteritems():
@@ -25,6 +26,7 @@ class PassiveOptionParser(OptionParser):
 
     def _process_args(self, largs, rargs, values):
         """little hack to support all --some_option=value parameters"""
+
         while rargs:
             arg = rargs[0]
             if arg == "--":
@@ -50,6 +52,7 @@ class PassiveOptionParser(OptionParser):
 
 def main(argv=None, **kwargs):
     """kwargs are default options that can be overriden with passing --some_option to cmdline"""
+
     argv = argv or list(sys.argv[1:])
     commands = list(api.__all__)
     commands.sort()