is an example for ``?sysv``

    >>> a = rng.random((1000, 1000))
    >>> b = rng.random((1000, 1)) * 1j
    >>> # We pick up zsysv and zsysv_lwork due to b array
    ... xsysv, xlwork = LA.get_lapack_funcs(('sysv', 'sysv_lwork'), (a, b))
    >>> opt_lwork, _ = xlwork(a.shape[0])  # returns a complex for 'z' prefix
    >>> udut, ipiv, x, info = xsysv(a, b, lwork=int(opt_lwork.real))

    Ú	preferredz