code: def __pad_value(value, pad_len_multiple, pad_char):
      
      assert pad_len_multiple > 0
      assert len(pad_char) == 1
      padding_length = (pad_len_multiple -
                        (len(value) % pad_len_multiple)) % pad_len_multiple
      return value + pad_char * padding_length
docs: Add padding characters to the value if needed.
  
      Args:
        value: The string value to be padded.
        pad_len_multiple: Pad the result so its length is a multiple
            of pad_len_multiple.
        pad_char: The character to use for padding.
  
      Returns:
        The string value with padding characters added.