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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 access_labels(self):
 """List of labels used to access the Port Returns ------- list of str Strings that can be used to access this Port relative to self.root """

        access_labels = []
        for referrer in self.referrers:
            referrer_labels = [key for key, val in self.root.labels.items()
                               if val == referrer]
            port_labels = [key for key, val in referrer.labels.items()
                           if val == self]
            if referrer is self.root:
                for label in port_labels:
                    access_labels.append("['{}']".format(label))
            for label in itertools.product(referrer_labels, port_labels):
                access_labels.append("['{}']".format("']['".join(label)))

        return access_labels