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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 getArc(self, prom, sig):
 """ Returns the arcs between a promissor and a significator. Should uses the object creation functions to build the objects. """

        res = self._arc(prom, sig)
        res.update({
            'prom': prom['id'],
            'sig': sig['id']
        })
        return res