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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_from_refresh(self) -> Tuple[str, float]: """Uses the stored refresh token to get a new access token. This method assumes that the refresh token exists. Args: None Returns: new access token and expiration time (from now) """

        headers = self._get_authorization_headers()
        data = {
            'grant_type': 'refresh_token',
            'refresh_token': self.refresh_token
        }
        r = self.session.post(self.TOKEN_URL, headers=headers, data=data)
        response_data = r.json()
        return (response_data['access_token'], response_data['expires_in'])