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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 on_if(self, node):
 # ('test', 'body', 'orelse') """Regular if-then-else statement."""

        block = node.body
        if not self.run(node.test):
            block = node.orelse
        for tnode in block:
            self.run(tnode)