'Tries to load the actual migration module'

def migration(self):

    full_name = self.full_name()
    try:
        migration = sys.modules[full_name]
    except KeyError:
        try:
            migration = __import__(full_name, {}, {}, ['Migration'])
        except ImportError as e:
            raise exceptions.UnknownMigration(self, sys.exc_info())
        except Exception as e:
            raise exceptions.BrokenMigration(self, sys.exc_info())
    migration._ = (lambda x: x)
    migration.datetime = datetime_utils
    return migration
