private function clone(string $parameter, $value): self
    {
        $directives = clone $this;
        $directives->$parameter = $value;
        return $directives;
    }
private function clone(string $parameter, $value): self
    {
        $directives = clone $this;
        $directives->$parameter = $value;
        return $directives;
    }
private function clone ( string $ parameter , $ value ) : self { $ directives = clone $ this ; $ directives -> $ parameter = $ value ; return $ directives ; }
Shorthand function to clone the current instance with a modified parameter.

@param string $parameter The name of the parameter to modify
@param mixed $value The value to set the parameter to

@return self The new modified instance
Shorthand function to clone the current instance with a modified parameter .