def ToJsonString(self):
    """Converts Duration to string format.

    Returns:
      A string converted from self. The string format will contains
      3, 6, or 9 fractional digits depending on the precision required to
      represent the exact Duration value. For example: "1s", "1.010s",
      "1.000000100s", "-3.100s"
    """
    _CheckDurationValid(self.seconds, self.nanos)
    if self.seconds < 0 or self.nanos < 0:
      result = '-'
      seconds = - self.seconds + int((0 - self.nanos) // 1e9)
      nanos = (0 - self.nanos) % 1e9
    else:
      result = ''
      seconds = self.seconds + int(self.nanos // 1e9)
      nanos = self.nanos % 1e9
    result += '%d' % seconds
    if (nanos % 1e9) == 0:
      # If there are 0 fractional digits, the fractional
      # point '.' should be omitted when serializing.
      return result + 's'
    if (nanos % 1e6) == 0:
      # Serialize 3 fractional digits.
      return result + '.%03ds' % (nanos / 1e6)
    if (nanos % 1e3) == 0:
      # Serialize 6 fractional digits.
      return result + '.%06ds' % (nanos / 1e3)
    # Serialize 9 fractional digits.
    return result + '.%09ds' % nanos
Converts Duration to string format.

    Returns:
      A string converted from self. The string format will contains
      3, 6, or 9 fractional digits depending on the precision required to
      represent the exact Duration value. For example: "1s", "1.010s",
      "1.000000100s", "-3.100s"
    
deps/protobuf/python/google/protobuf/internal/well_known_types.py