How to use the simpleai.search.traditional.astar function in simpleai

def test_astar_graph_execution_with_repeated_states_chooses_better_state(self):
        result = astar(self.graph_problem, graph_search=True)
        self.assertEquals(result.state, self.graph_problem.goal)

def test_astar_graph_inadmissible_heuristic(self):
        v = TestViewer([[('s', 0)], [('l', 26), ('a', 15)], [('r', 42), ('a', 15)]])
        self.graph_problem.heuristic_dict = DummyGraphProblem.inadmissible
        result = astar(self.graph_problem, graph_search=True, viewer=v)
        self.assertEquals(result.state, self.graph_problem.goal)

def test_astar_tree_inadmissible_heuristic(self):
        v = TestViewer([[('s', 0)], [('l', 26), ('a', 15)], [('r', 42), ('a', 15), ('a', 36), ('s', 52)]])
        self.graph_problem.heuristic_dict = DummyGraphProblem.inadmissible
        result = astar(self.graph_problem, graph_search=False, viewer=v)
        self.assertEquals(result.state, self.graph_problem.goal)

def test_astar_graph_consistent_heuristic(self):
        v = TestViewer([[('s', 0)], [('a', 15), ('l', 26)], [('l', 25)], [('r', 41)]])
        self.graph_problem.heuristic_dict = DummyGraphProblem.consistent
        result = astar(self.graph_problem, graph_search=True, viewer=v)
        self.assertEquals(result.state, self.graph_problem.goal)

def test_astar(self):
        result = astar(self.problem)
        self.assertEquals(result.state, GOAL)

def test_astar_graph_doesnt_repeat_states_in_explore_set(self):
        v = TestViewer([[('s', 0)], [('l', 26), ('a', 15)], [('a', 15), ('r', 42)], [('r', 42)]])
        self.graph_problem.heuristic_dict = DummyGraphProblem.inconsistent
        result = astar(self.graph_problem, graph_search=True, viewer=v)
        self.assertEquals(result.state, self.graph_problem.goal)