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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def Vdiff(D1, D2):
 """ finds the vector difference between two directions D1,D2 """

    A = dir2cart([D1[0], D1[1], 1.])
    B = dir2cart([D2[0], D2[1], 1.])
    C = []
    for i in range(3):
        C.append(A[i] - B[i])
    return cart2dir(C)