human
Solve the following python programming problem given the following code:
def test_non_numpy_sum() : 
    def fun(x, y) : 
        return to_scalar (sum ([x, y])) 
d_fun = (lambda x, y : to_scalar (grad (fun) (x, y))) 
    mat1 = npr.randn (10, 11) 
    mat2 = npr.randn (10, 11) 
    check_grads (mat2, mat1, mat2) 
    check_grads (d_fun, mat1, mat2) 

    
    

    Fix the buggy line: check_grads (mat2, mat1, mat2)
assistant
#Here is Python code to fix the buggy line: check_grads (mat2, mat1, mat2)
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check_grads (fun, mat1, mat2)