Using Rector, I'm trying to convert the following.
$integer = some_made_up_function_call($parm1, $parm2);
Into this:
$integer = $parm1->made_up_method_call($parm2)['hard_coded_index'];
My issue is with the ['hard_coded_index'] at the end. I can’t figure out how to accomplish that. What I have so far is.
public function refactor(Node $node): ?Node
{
    if (! $this->isName($node->name, 'some_made_up_function_call')) {
        return null;
    }
    $firstParameter = new Node\Expr\Variable($node->args[0]->value->name);
    return new Node\Expr\MethodCall(
        $firstParameter, 
        'made_up_method_call', 
        [$node->args[1]]
    );
}
 
                        
All right, I figured it out...