'Return the index of *handle* in the list of this ROI\'s handles.'

def indexOfHandle(self, handle):

    if isinstance(handle, Handle):
        index = [i for (i, info) in enumerate(self.handles) if (info['item'] is handle)]
        if (len(index) == 0):
            raise Exception('Cannot    return    handle    index;    not    attached    to    this    ROI')
        return index[0]
    else:
        return handle
