docs: def validate_timeout_or_zero(option, value):
      """Validates a timeout specified in milliseconds returning
      a value in floating point seconds for the case where None is an error
      and 0 is valid. Setting the timeout to nothing in the URI string is a
      config error.
      """
      if value is None:
          raise ConfigurationError("%s cannot be None" % (option, ))
      if value == 0 or value == "0":
          return 0
      return validate_positive_float(option, value) / 1000.0