<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def request(self, url, method="GET", params=None, headers=None, is_signed=True):
 """ Make a request against ``url``. By default, the request is signed with an access token, but can be turned off by passing ``is_signed=False``. """

        params = params or {}
        headers = headers or {}
        
        if is_signed:
            params.update(self.get_signing_params())
        
        if method.upper() == "GET":
            url = '%s?%s' % (url, urllib.urlencode(params))
            return self.client().request(url, method=method, headers=headers)
        return self.client().request(url, method, body=urllib.urlencode(params), headers=headers)