def get_liqpay_sign(payment_data, action):
    import base64
    import hashlib

    """
    action == 'to_send' when use sign for submit form to PB
    action == 'to_validate' when use sign to validate PB response
    """

    str_for_sign = ''

    if action == "to_send":
        keys_for_sign = ['private_key', 'amount', 'currency', 'public_key',
                         'order_id', 'type', 'description', 'result_url',
                         'server_url']
    elif action == "to_validate":
        keys_for_sign = ['private_key', 'amount', 'currency', 'public_key',
                         'order_id', 'type', 'description', 'status',
                         'transaction_id', 'sender_phone']

    for key in keys_for_sign:
        str_for_sign += str(payment_data[key])

    result = base64.b64encode(
        hashlib.sha1(str_for_sign).digest()
    )
    return result


----

                payment_data = {
                    "public_key": merchant_data.get("merchant_id"),
                    "private_key": merchant_data.get("merchant_sign"),
                    "amount": temp_order.pay_total(),
                    "currency": temp_order.currency,
                    "order_id": temp_order.id,
                    "type": "buy",
                    "order": temp_order,
                    "description": "Oplata zakaza #%s" % temp_order.number,
                    "result_url": result_url,
                    "server_url": server_url,
                }

                signature = get_liqpay_sign(payment_data, 'to_send')