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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 calledBefore(self, spy):
 #pylint: disable=invalid-name """ Compares the order in which two spies were called E.g. spy_a() spy_b() spy_a.calledBefore(spy_b) # True spy_b.calledBefore(spy_a) # False spy_a() spy_b.calledBefore(spy_a) # True Args: a Spy to compare with Return: Boolean True if this spy's first call was called before the given spy's last call """

        this_call = self.firstCall if self.firstCall is not None else False
        given_call = spy.lastCall if spy.lastCall is not None else False
        return (this_call and not given_call) or (this_call and given_call and this_call.callId < given_call.callId)