'Pop values from stack at end of nesting.
Called to indicate the end of a nested scope.
Returns:
Previously pushed value at the top of the stack.'

def _Pop(self):

    assert ((self._stack != []) and (self._stack is not None))
    (token, value) = self._stack.pop()
    if self._stack:
        self._top = self._stack[(-1)]
    else:
        self._top = None
    return value
