src/PaymentSlip.php
protected function isIntOrFloat($parameter, $varName)
    {
        if ((!is_int($parameter) && !is_float($parameter))) {
            throw new InvalidArgumentException(
                sprintf(
                    '$%s is neither an integer nor a float.',
                    $varName
                )
            );
        }
    }
protected function isIntOrFloat($parameter, $varName)
    {
        if ((!is_int($parameter) && !is_float($parameter))) {
            throw new InvalidArgumentException(
                sprintf(
                    '$%s is neither an integer nor a float.',
                    $varName
                )
            );
        }
    }
protected function isIntOrFloat ( $ parameter , $ varName ) { if ( ( ! is_int ( $ parameter ) && ! is_float ( $ parameter ) ) ) { throw new InvalidArgumentException ( sprintf ( '$%s is neither an integer nor a float.' , $ varName ) ) ; } }
Verify that a given parameter is an integer or a float

@param mixed $parameter The given parameter to validate.
@param string $varName The name of the variable.
@return true If the parameter is either  an integer or a float.
@throws InvalidArgumentException If the parameter is neither an integer nor a float.
Verify that a given parameter is an integer or a float