https://docs.mollie.com/reference/v2/payments-api/create-payment
function(array $data, string $customer_id = NULL, string $mandate_id = NULL)
{
if ($customer_id) {
$data = array_merge($data, ['customerId' => $customer_id]);
}
if ($mandate_id) {
$data = array_merge($data, ['mandateId' => $mandate_id]);
}
$payment = $this->mollie->payments->create($data);
return X::toArray($payment);
}