code: def map_counterpart(string, config_file=None):
      
      skip_home_flag = config_file is not None
      mapping = get_counterpart_mapping(config_file, skip_home_flag)
      return mapping[string]
docs: One-step look-up; returns a counterpart for the given string, as
      determined from the config file(s) via ConfigFromFile.
      config_file is read after ~/.counterc, if present, making its
      values take precedence over those in ~/.counterc.
  
      :param string: The string to find the counterpart of.
      :param config_file: Path to a config file to guide the mapping.
             Default is to use ./counterc and/or ~/.countrc.
      :return: String value, the counterpart of the input string.