code: def _ParseNumericOption(cls, options, argument_name, default_value=None):
      
      argument_value = getattr(options, argument_name, None)
      if argument_value is None:
        return default_value
  
      if not isinstance(argument_value, py2to3.INTEGER_TYPES):
        raise errors.BadConfigOption(
            'Unsupported option: {0:s} integer type required.'.format(
                argument_name))
  
      return argument_value
docs: Parses a numeric command line argument.
  
      Args:
        options (argparse.Namespace): parser options.
        argument_name (str): name of the command line argument.
        default_value (Optional[int]): default value of the command line argument.
  
      Returns:
        int: command line argument value or the default value if the command line
            argument is not set
  
      Raises:
        BadConfigOption: if the command line argument value cannot be converted
            to a Unicode string.