The python request url failed due to the lack of ca certificate

Environments Windows
1

My ci script will download package from the host of www.nuget.org, but it failed due to the lack of ca certificate

  Traceback (most recent call last):
        File "..\deps\windows-install.py", line 22, in <module>
          filedata = urllib2.urlopen(librdkafkaNugetUrl)
        File "C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\opt\lib\python2.7/urllib2.py", line 154, in urlopen
          return opener.open(url, data, timeout)
        File "C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\opt\lib\python2.7/urllib2.py", line 431, in open
          response = self._open(req, data)
        File "C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\opt\lib\python2.7/urllib2.py", line 449, in _open
          '_open', req)
        File "C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\opt\lib\python2.7/urllib2.py", line 409, in _call_chain
          result = func(*args)
        File "C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\opt\lib\python2.7/urllib2.py", line 1240, in https_open
          context=self._context)
        File "C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\opt\lib\python2.7/urllib2.py", line 1197, in do_open
          raise URLError(err)
    urllib2.URLError : <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:581)>

The entire log contains such error is : https://travis-ci.org/yunnysunny/node-rdkafka/jobs/504583885