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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 eval(self, packet):
 """Returns the result of evaluating this PacketExpression in the context of the given Packet. """

        try:
            context = createPacketContext(packet)
            result  = eval(self._code, packet._defn.globals, context)
        except ZeroDivisionError:
            result = None

        return result