'Advance to the next item in a repeated section.
Raises:
StopIteration if there are no more elements'

def Next(self):

    stacktop = self.stack[(-1)]
    if (stacktop.index == (-1)):
        stacktop = _Frame(None, index=0)
        self.stack.append(stacktop)
    context_array = self.stack[(-2)].context
    if (stacktop.index == len(context_array)):
        self.stack.pop()
        raise StopIteration
    stacktop.context = context_array[stacktop.index]
    stacktop.index += 1
    return True
