code: def user_agent_info(sdk_version, custom_user_agent):
      # type: (str, str) -> str
      
      python_version = ".".join(str(x) for x in sys.version_info[0:3])
      user_agent = "ask-python/{} Python/{}".format(
          sdk_version, python_version)
      if custom_user_agent is None:
          return user_agent
      else:
          return user_agent + " {}".format(custom_user_agent)
docs: Return the user agent info along with the SDK and Python
      Version information.
  
      :param sdk_version: Version of the SDK being used.
      :type sdk_version: str
      :param custom_user_agent: Custom User Agent string provided by
          the developer.
      :type custom_user_agent: str
      :return: User Agent Info string
      :rtype: str