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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 save_bt_addr(self, packet, bt_addr):
 """Add to the list of mappings."""

        if isinstance(packet, EddystoneUIDFrame):
            # remove out old mapping
            new_mappings = [m for m in self.eddystone_mappings if m[0] != bt_addr]
            new_mappings.append((bt_addr, packet.properties))
            self.eddystone_mappings = new_mappings