我试图在python中使用WSDL包。我得到的错误与其他软件包相关联，我不确定如何跟踪问题。这是错误：
python flightaware.py
http://flightxml.flightaware.com/soap/FlightXML2
__main__.myHTTPTransport
Traceback (most recent call last):
File "flightaware.py", line 37, in <module>
DF = WSDL.Proxy(wsdlFile, transport=myHTTPTransport)
File "/usr/local/lib/python2.7/distpackages/SOAPpy0.12.22py2.7.egg/SOAPpy/WSDL.py", line 74, in __init__
stream = urllib.URLopener(key_file=config.SSL.key_file, cert_file=config.SSL.cert_file).open(wsdlsource)
File "/usr/lib/python2.7/urllib.py", line 203, in open
name = 'open_' + urltype
TypeError: cannot concatenate 'str' and 'NoneType' objects
任何想法都会有所帮助。