code: def _CopyField(field, number=None):
    
    positional_args, kwargs = _GetFieldAttributes(field)
    number = number or field.number
    positional_args.append(number)
    return field.__class__(*positional_args, **kwargs)
docs: Copies a (potentially) owned ProtoRPC field instance into a new copy.
  
    Args:
      field: A ProtoRPC message field to be copied.
      number: An integer for the field to override the number of the field.
          Defaults to None.
  
    Raises:
      TypeError: If the field is not an instance of messages.Field.
  
    Returns:
      A copy of the ProtoRPC message field.