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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 add(self, actors):
 """Append input object to the internal list of actors to be shown. :return: returns input actor for possible concatenation. """

        if utils.isSequence(actors):
            for a in actors:
                if a not in self.actors:
                    self.actors.append(a)
            return None
        else:
            self.actors.append(actors)
            return actors