docs: def readCfgJson(cls, working_path):
          """Read cmWalk configuration data of a working directory from a json file.
  
          :param working_path: working path for reading the configuration data.
          :return: the configuration data represented in a json object, None if the configuration files does not
                   exist.
          """
  
          cfg_json_filename = os.path.join(working_path, cls.CFG_JSON_FILENAME)
          if os.path.isfile(cfg_json_filename):
              with open(cfg_json_filename) as json_file:
                  cfg = json.load(json_file)
                  return cfg
          return None