def _read_object(self, path):
    '''read in object from file at `path`'''
    if not os.path.exists(path):
      return None

    if os.path.isdir(path):
      raise RuntimeError(path % '%s is a directory, not a file.')

    with open(path) as f:
      file_contents = f.read()

    return file_contents
dataset/ETHPy150Open datastore/datastore/datastore/filesystem/__init__.py/FileSystemDatastore._read_object/swapped operands of `%`