def test_negative_scalar_index(adata, index: int, obs: bool):
    pos_index = index + (adata.n_obs if obs else adata.n_vars)

    if obs:
        adata_pos_subset = adata[pos_index]
        adata_neg_subset = adata[index]
    else:
        adata_pos_subset = adata[:, pos_index]
        adata_neg_subset = adata[:, index]

    np.testing.assert_array_equal(
        adata_pos_subset.obs_names, adata_neg_subset.obs_names
    )
    np.testing.assert_array_equal(
        adata_pos_subset.var_names, adata_neg_subset.var_names
    )
def __init__(self, head):
        self.head = head
        self.lsize = 0
        while head.next:
            head = head.next
            self.lsize += 1

        self.m1_idx = None
        self.m2_idx = None
        if self.lsize > self._largesize:
            self.m1_idx = self.lsize / 3   # start from 1/3
            self.m1 = self._getN(self.m1_idx)
            self.m2_idx = self.m1_idx * 2  # start from 2/3
            self.m2 = self._getN(self.m2_idx)