code: def get_all_migrations(path, databases=None):
      
      # database: [(number, full_path)]
      possible_migrations = defaultdict(list)
      
      try:
          in_directory = sorted(get_file_list(path))
      except OSError:
          import traceback
          print "An error occurred while reading migrations from %r:" % path
          traceback.print_exc()
          return {}
      
      # Iterate through our results and discover which migrations are
      # actually runnable
      for full_path in in_directory:
          child_path, script = os.path.split(full_path)
          name, ext = os.path.splitext(script)
          
          # the database component is default if this is in the root directory
          # is <directory> if in a subdirectory
          if path == child_path:
              db = DEFAULT_DB_ALIAS
          else:
              db = os.path.split(child_path)[-1]
          
          # filter by database if set
          if databases and db not in databases:
              continue
          
          match = MIGRATION_NAME_RE.match(name)
          if match is None:
              raise MigrationError("Invalid migration file prefix %r "
                                   "(must begin with a number)" % name)
          
          number = int(match.group(1))
          if ext in [".sql", ".py"]:
              possible_migrations[db].append((number, full_path))
      
      return possible_migrations
docs: Returns a dictionary of database => [migrations] representing all
      migrations contained in ``path``.