<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def Next(self):
 """Advance to the next item in a repeated section. Raises: StopIteration if there are no more elements """

        stacktop = self.stack[-1]
        
        # Now we're iterating -- push a new mutable object onto the stack
        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