Check if rightBarButtonItem exists or not

Question

Is there a way to check if the current view already has a right bar button, something like:

if (FOO_CODE.rightBarButtonItem != nil) {
    // don't create one
} else {
    // create one
}

Answer 1

if (self.navigationItem.rightBarButtonItem)

has the same effect, testing equality to nil is redundant

Answer 2

if (self.navigationItem.rightBarButtonItem != nil)
{
   // I exists
} else {
   // I don't exists
}