docs: def readExcel(usr_path=""):
      """
      Read Excel file(s)
      Enter a file path, directory path, or leave args blank to trigger gui.
  
      :param str usr_path: Path to file / directory (optional)
      :return str cwd: Current working directory
      """
      global cwd, files
      start = clock()
      files[".xls"] = []
      __read(usr_path, ".xls")
      end = clock()
      logger_benchmark.info(log_benchmark("readExcel", start, end))
      return cwd