private function assertMethodCallable($class_name, $method, $callable)
    {
        if (
            class_exists($class_name)
            && ! (method_exists($class_name, $method) || is_callable([$class_name, $method]))
        ) {
            throw Exception\InvalidCallable::forCallable($callable);
        }
    }
private function assertMethodCallable($class_name, $method, $callable)
    {
        if (
            class_exists($class_name)
            && ! (method_exists($class_name, $method) || is_callable([$class_name, $method]))
        ) {
            throw Exception\InvalidCallable::forCallable($callable);
        }
    }
private function assertMethodCallable ( $ class_name , $ method , $ callable ) { if ( class_exists ( $ class_name ) && ! ( method_exists ( $ class_name , $ method ) || is_callable ( [ $ class_name , $ method ] ) ) ) { throw Exception \ InvalidCallable :: forCallable ( $ callable ) ; } }
Ensure method existence only if class is available.

@param string       $class_name
@param string       $method
@param string|array $callable
@throws \Brain\Monkey\Name\Exception\InvalidCallable
@throws \Brain\Monkey\Name\Exception\NotInvokableObjectAsCallback
Ensure method existence only if class is available .