code: def _get_node_name_from_tensor(tensor_name):
    
    result = re.match(r"([^:]*):\d+$", tensor_name)
    if not result:
      raise ValueError(
          "Unexpected format for tensor name. Expected node_name:output_number. "
          "Got %r" % tensor_name)
    return result.group(1)
docs: tensor_name must have format node_name:output_number. Returns node_name.