def METHOD_NAME(self):
    # new empty dictionaries must all have an unique version
    empty1 = self.new_dict()
    empty2 = self.new_dict()
    empty3 = self.new_dict()
    # non-empty dictionaries must also have an unique version
    nonempty1 = self.new_dict(x='x')
    nonempty2 = self.new_dict(x='x', y='y')