code: def _ParseSourcePathOption(self, options):
      
      self._source_path = self.ParseStringOption(options, self._SOURCE_OPTION)
      if not self._source_path:
        raise errors.BadConfigOption('Missing source path.')
  
      self._source_path = os.path.abspath(self._source_path)
docs: Parses the source path option.
  
      Args:
        options (argparse.Namespace): command line arguments.
  
      Raises:
        BadConfigOption: if the options are invalid.