code: def create_token(self, request, refresh_token=False, **kwargs):
          
          if "save_token" in kwargs:
              warnings.warn("`save_token` has been deprecated, it was not called internally."
                            "If you do, call `request_validator.save_token()` instead.",
                            DeprecationWarning)
  
          if callable(self.expires_in):
              expires_in = self.expires_in(request)
          else:
              expires_in = self.expires_in
  
          request.expires_in = expires_in
  
          token = {
              'access_token': self.token_generator(request),
              'expires_in': expires_in,
              'token_type': 'Bearer',
          }
  
          # If provided, include - this is optional in some cases https://tools.ietf.org/html/rfc6749#section-3.3 but
          # there is currently no mechanism to coordinate issuing a token for only a subset of the requested scopes so
          # all tokens issued are for the entire set of requested scopes.
          if request.scopes is not None:
              token['scope'] = ' '.join(request.scopes)
  
          if refresh_token:
              if (request.refresh_token and
                      not self.request_validator.rotate_refresh_token(request)):
                  token['refresh_token'] = request.refresh_token
              else:
                  token['refresh_token'] = self.refresh_token_generator(request)
  
          token.update(request.extra_credentials or {})
          return OAuth2Token(token)
docs: Create a BearerToken, by default without refresh token.
  
          :param request: OAuthlib request.
          :type request: oauthlib.common.Request
          :param refresh_token: