code: def _format_operation(operation, parameters=None):
      
      if parameters is None:
          return operation
  
      if isinstance(parameters, collections_abc.Mapping):
          return _format_operation_dict(operation, parameters)
  
      return _format_operation_list(operation, parameters)
docs: Formats parameters in operation in way BigQuery expects.
  
      :type: str
      :param operation: A Google BigQuery query string.
  
      :type: Mapping[str, Any] or Sequence[Any]
      :param parameters: Optional parameter values.
  
      :rtype: str
      :returns: A formatted query string.
      :raises: :class:`~google.cloud.bigquery.dbapi.ProgrammingError`
          if a parameter used in the operation is not found in the
          ``parameters`` argument.