Python 爬虫初学，urlopen 出错？

Question

代码如下：
import urllib.request


response = urllib.request.urlopen('https://www.python.org')
print(type(response))
print(response.read().decode('utf-8'))

错误信息如下：

Traceback (most recent call last):

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1317, in do_open

    encode_chunked=req.has_header('Transfer-encoding'))

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1229, in request

    self._send_request(method, url, body, headers, encode_chunked)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1275, in _send_request

    self.endheaders(body, encode_chunked=encode_chunked)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1224, in endheaders

    self._send_output(message_body, encode_chunked=encode_chunked)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1016, in _send_output

    self.send(msg)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 956, in send

    self.connect()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/http/client.py", line 1392, in connect

    server_hostname=server_hostname)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 412, in wrap_socket

    session=session

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 853, in _create

    self.do_handshake()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 1117, in do_handshake

    self._sslobj.do_handshake()

ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "<input>", line 1, in <module>

  File "/Applications/PyCharm.app/Contents/helpers/pydev/_pydev_bundle/pydev_umd.py", line 197, in runfile

    pydev_imports.execfile(filename, global_vars, local_vars)  # execute the script

  File "/Applications/PyCharm.app/Contents/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile

    exec(compile(contents+"\n", file, 'exec'), glob, loc)

  File "/Users/awake/PycharmProjects/untitled/venv/Hello.py", line 4, in <module>

    response = urllib.request.urlopen('https://www.python.org')

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 222, in urlopen

    return opener.open(url, data, timeout)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 525, in open

    response = self._open(req, data)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 543, in _open

    '_open', req)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 503, in _call_chain

    result = func(*args)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1360, in https_open

    context=self._context, check_hostname=self._check_hostname)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1319, in do_open

    raise URLError(err)

urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)>