理解Pycharm推斷類型提示

Question

我想在“快速文檔”窗口中了解PyCharm中帶有推斷類型的內容。

使用下面的功能，我在快速文檔中看到以下內容：

參數host顯示為我期望的Optional[str] ，但auth和version僅顯示str | None str | None 。 技術上（我相信）兩者都是正確的，但為什么這些類似論點之間存在差異？

你會注意到我試圖改變版本的類型提示只是為了看看是否有任何區別。

我錯過了類型提示的工作原理嗎？
有什么方法我可以獲得Optional[str]顯示auth和version ？

def getBaseUrl(service, host=None, auth=None, version=None):
    """
    Defaulted arguments will automatically fetch the values from config 

    :param str service: wms, wfs
    :param str or None host:    [internal | external | {user submitted host}] -
                                internal and external will use the config file to automatically determine
                                anything else will be assumed as a server address including possible port.
    :param str or None auth:    basic, digest, oauth 
                                anything else will raise exception
    :param version: eg wms_v1, wfs_v1
    :type version:  str or None
    :return: base url for use in the gis Webservice
    """
    assert service.lower() == 'wms' or service.lower() == 'wfs', "Unsupported service: %s" % service

    internalhost = cfg.get('GIS', 'internalhost')
    externalhost = cfg.get('GIS', 'externalhost')

    if host is None:
        host = cfg.get('GIS', 'host')
    if version is None:
        version = cfg.get(service, 'version')

    if host == "internal":
        host = "{host}".format(host=internalhost)

    elif host == 'external':
        host = "{host}".format(host=externalhost)

    else:
        host = "{host}".format(host=host)

    return buildBaseUrl(host=host, version=version, auth=auth, service=service)

Answer 1

看起來這確實是Pycharm的一個錯誤。 待修訂於2016.2發布。

https://youtrack.jetbrains.com/issue/PY-17705