code: def _create_ssl_context(self) -> Optional[SSLContext]:
          
          ssl_context = None
          if self.cfg.is_ssl:
              ssl_context = SSLContext(self.cfg.ssl_version)
              ssl_context.load_cert_chain(self.cfg.certfile, self.cfg.keyfile)
              if self.cfg.ca_certs:
                  ssl_context.load_verify_locations(self.cfg.ca_certs)
              if self.cfg.ciphers:
                  ssl_context.set_ciphers(self.cfg.ciphers)
              ssl_context.set_alpn_protocols(['http/1.1'])
          return ssl_context
docs: 创建 ssl