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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 _associate_placeable(self, location):
 """ Saves a reference to a placeable """

        if not location:
            return

        placeable, _ = unpack_location(location)
        self.previous_placeable = placeable
        if not self.placeables or (placeable != self.placeables[-1]):
            self.placeables.append(placeable)