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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pop_fbo(self):
 """ Pop an FBO from the stack. """

        fbo = self._fb_stack.pop()
        fbo[0].deactivate()
        self.pop_viewport()
        if len(self._fb_stack) > 0:
            old_fbo = self._fb_stack[-1]
            old_fbo[0].activate()
        
        self._update_transforms()
        return fbo