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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 d2Ibr_dV2(Ybr, V, lam):
 """ Computes 2nd derivatives of complex branch current w.r.t. voltage. """

    nb = len(V)
    diaginvVm = spdiag(div(matrix(1.0, (nb, 1)), abs(V)))

    Haa = spdiag(mul(-(Ybr.T * lam), V))
    Hva = -1j * Haa * diaginvVm
    Hav = Hva
    Hvv = spmatrix([], [], [], (nb, nb))

    return Haa, Hav, Hva, Hvv