code: def _prepare_conn(self, conn):
          
  
          if isinstance(conn, VerifiedHTTPSConnection):
              conn.set_cert(key_file=self.key_file,
                            cert_file=self.cert_file,
                            cert_reqs=self.cert_reqs,
                            ca_certs=self.ca_certs,
                            ca_cert_dir=self.ca_cert_dir,
                            assert_hostname=self.assert_hostname,
                            assert_fingerprint=self.assert_fingerprint)
              conn.ssl_version = self.ssl_version
          return conn
docs: Prepare the ``connection`` for :meth:`urllib3.util.ssl_wrap_socket`
          and establish the tunnel if proxy is used.