after pip3 install otree, it worked, but when procedding the next step with:
otree startproject oTree 


terminal told me:

URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1000)>.

The full error is as below:Include sample games? (y or n): y
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 1344, in do_open
    h.request(req.get_method(), req.selector, req.data, headers,
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/http/client.py", line 1327, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/http/client.py", line 1373, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/http/client.py", line 1322, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/http/client.py", line 1081, in _send_output
    self.send(msg)
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/http/client.py", line 1025, in send
    self.connect()
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/http/client.py", line 1468, in connect
    self.sock = self._context.wrap_socket(self.sock,
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/ssl.py", line 455, in wrap_socket
    return self.sslsocket_class._create(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/ssl.py", line 1046, in _create
    self.do_handshake()
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/ssl.py", line 1321, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1000)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.12/bin/otree", line 8, in <module>
    sys.exit(execute_from_command_line())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/otree/main.py", line 112, in execute_from_command_line
    call_command(cmd, *argv[2:])
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/otree/cli/base.py", line 32, in call_command
    module.Command().outer_handle(args)
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/otree/cli/base.py", line 10, in outer_handle
    return self.handle(**vars(options))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/otree/cli/startproject.py", line 46, in handle
    download_from_github(dest)
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/otree/cli/startproject.py", line 70, in download_from_github
    resp = urlopen(f"https://github.com/oTree-org/oTree/archive/{branch_name}.zip")
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 215, in urlopen
    return opener.open(url, data, timeout)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 515, in open
    response = self._open(req, data)
               ^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 532, in _open
    result = self._call_chain(self.handle_open, protocol, protocol +
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 492, in _call_chain
    result = func(*args)
             ^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 1392, in https_open
    return self.do_open(http.client.HTTPSConnection, req,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/urllib/request.py", line 1347, 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:1000)>
LM1049479:~ ydeng$

Solved.