human
Solve the following python programming problem given the following code:
def check_traceback(self, x_data) : 
    xp = cuda.get_array_module (x_data) 
    class DummyFunction (chainer.Function) : 
        label = 'dummy_function' 
        def forward(self, inputs) : 
            return (xp.array (1, np.float32),) 
def backward(self, inputs, grads) : 
            return (xp.array ([1, 2], np.float32),) 
x = chainer.Variable (x_data) 
    line = (inspect.currentframe ().f_lineno + 1) 
    y = DummyFunction () (x) 
    try : 
        y.backward () 
        self.fail () 
except ValueError as e : 
        self.assertIn ('Stacktrace', str (line)) 
        self.assertIn (('line %d' % line), str (e)) 

    
    

    Fix the buggy line: self.assertIn ('Stacktrace', str (line))
assistant
#Here is Python code to fix the buggy line: self.

self.assertIn ('Stacktrace', str (e))