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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_access_token(self, verifier=None):
 """ Fetch an access token from `self.access_token_url`. """

        
        response, content = self.client(verifier).request(
            self.access_token_url, "POST")
        
        content = smart_unicode(content)

        if not response['status'] == '200':
            raise OAuthError(_(
                u"Invalid status code %s while obtaining access token from %s: %s") % 
                (response['status'], self.access_token_url, content))
        
        token = dict(urlparse.parse_qsl(content))
        
        
        return (oauth.Token(token['oauth_token'], token['oauth_token_secret']),
            token)