def withdraw(self, amount, currency, payment_method_id):
        """ Withdraw funds to a payment method.

        See AuthenticatedClient.get_payment_methods() to receive
        information regarding payment methods.

        Args:
            amount (Decimal): The amount to withdraw.
            currency (str): Currency type (eg. 'BTC')
            payment_method_id (str): ID of the payment method.

        Returns:
            dict: Withdraw details. Example::
                {
                    "id":"593533d2-ff31-46e0-b22e-ca754147a96a",
                    "amount": "10.00",
                    "currency": "USD",
                    "payout_at": "2016-08-20T00:31:09Z"
                }

        """
        params = {'amount': amount,
                  'currency': currency,
                  'payment_method_id': payment_method_id}
        return self._send_message('post', '/withdrawals/payment-method',
                                  data=json.dumps(params))
 Withdraw funds to a payment method.

        See AuthenticatedClient.get_payment_methods() to receive
        information regarding payment methods.

        Args:
            amount (Decimal): The amount to withdraw.
            currency (str): Currency type (eg. 'BTC')
            payment_method_id (str): ID of the payment method.

        Returns:
            dict: Withdraw details. Example::
                {
                    "id":"593533d2-ff31-46e0-b22e-ca754147a96a",
                    "amount": "10.00",
                    "currency": "USD",
                    "payout_at": "2016-08-20T00:31:09Z"
                }

        
cbpro/authenticated_client.py