def test_set_subset_obsm(adata, subset_func):
    init_hash = joblib.hash(adata)
    orig_obsm_val = adata.obsm["o"].copy()

    while True:
        subset_idx = slice_subset(adata.obs_names)
        if len(adata[subset_idx, :]) > 2:
            break
    subset = adata[subset_idx, :]

    internal_idx = _normalize_index(
        subset_func(np.arange(subset.obsm["o"].shape[0])), subset.obs_names
    )

    assert subset.is_view
    subset.obsm["o"][internal_idx] = 1
    assert not subset.is_view
    assert np.all(adata.obsm["o"] == orig_obsm_val)

    assert init_hash == joblib.hash(adata)
def voltage_fft(title, order, voltage, ax=0):
    """plot FFT harmonics of voltage"""
    if ax == 0:
        ax = plt.gca()
    ax.set_title('{} / V'.format(title))
    ax.grid(True)
    if max(order) < 5:
        order += [5]
        voltage += [0]
    try:
        bw = 2.5E-2*max(order)
        ax.bar(order, voltage, width=bw, align='center')
    except ValueError:  # empty sequence
        pass