docs: def _get_python_version_string():
      """
      Returns a string representation of the Python version.
  
      :return: "2.7.8" if python version is 2.7.8.
      :rtype string
      """
      version_info = sys.version_info
      return '.'.join(map(str, [version_info[0], version_info[1], version_info[2]]))