protected function _literalArgumentFunction($name, $expression, $types = [], $return = 'string')
    {
        if (!is_string($expression)) {
            $expression = [$expression];
        } else {
            $expression = [$expression => 'literal'];
        }

        return $this->_build($name, $expression, $types, $return);
    }
protected function _literalArgumentFunction($name, $expression, $types = [], $return = 'string')
    {
        if (!is_string($expression)) {
            $expression = [$expression];
        } else {
            $expression = [$expression => 'literal'];
        }

        return $this->_build($name, $expression, $types, $return);
    }
protected function _literalArgumentFunction ( $ name , $ expression , $ types = [ ] , $ return = 'string' ) { if ( ! is_string ( $ expression ) ) { $ expression = [ $ expression ] ; } else { $ expression = [ $ expression => 'literal' ] ; } return $ this -> _build ( $ name , $ expression , $ types , $ return ) ; }
Helper function to build a function expression that only takes one literal
argument.

@param string $name name of the function to build
@param mixed $expression the function argument
@param array $types list of types to bind to the arguments
@param string $return The return type for the function
@return \Cake\Database\Expression\FunctionExpression
Helper function to build a function expression that only takes one literal argument .