https://api.slack.com/methods/oauth.access

def access(self, client_id, client_secret, code, **kwargs):
        """ https://api.slack.com/methods/oauth.access
        """
        self.params.update({
            'client_id':     client_id,
            'client_secret': client_secret,
            'code':          code,
            })
        if kwargs:
            self.params.update(kwargs)
        return FromUrl('https://slack.com/api/oauth.access', self._requests)(data=self.params).post()