def add(self, other):
    self.domains = list(set((self.domains + other.domains)))
    self.tasks = list(set((self.tasks + other.tasks)))
    self.paths = list(set((self.paths + other.paths)))
def add(self, other):
    self.domains = list(set((self.domains + other.domains)))
    self.tasks = list(set((self.tasks + other.tasks)))
    self.paths = list(set((self.paths + other.paths)))