def METHOD_NAME(self, s, d1):
    """Copy method should copy values on a subset"""
    d2 = op2.Dat(s)
    ss = op2.Subset(s, list(range(1, nelems, 2)))
    d1.copy(d2, subset=ss)
    assert (d1.data_ro[ss.indices] == d2.data_ro[ss.indices]).all()
    assert (d2.data_ro[::2] == 0).all()