@staticmethod
def list_source_and_target_plates(picklist):
    """Return two lists: plates with resp. source wells and target wells.

        In the final animation, source plates will be on the left and target
        plates on the right.
        """
    source_plates = []
    target_plates = []
    seen_plates = set()
    for _transfer in picklist.transfers_list:
        source_plate = _transfer.source_well.plate
        target_plate = _transfer.destination_well.plate
        if source_plate not in seen_plates:
            source_plates.append(source_plate)
        if target_plate not in seen_plates:
            target_plates.append(target_plate)
        seen_plates.add(source_plate)
        seen_plates.add(target_plate)
    return source_plates, target_plates
