def __init__(self):
'''
instanciates with no params
'''
self.tree_model = TreatmentTreeModel()
#:a pointer to the treatment plan :doc:`ChartDataModel`
self.plan_tx_chartmodel = ChartDataModel()
#:a pointer to the treatment completed :doc:`ChartDataModel`
self.cmp_tx_chartmodel = ChartDataModel()
self._treatment_items = []
self._deleted_items = []
