def test_drop_obs_column():
    adata = ad.AnnData(np.array(X_list), obs=obs_dict, dtype="int32")

    subset = adata[:2]
    assert subset.is_view
    # returns a copy of obs
    assert subset.obs.drop(columns=["oanno1"]).columns.tolist() == ["oanno2", "oanno3"]
    assert subset.is_view
    # would modify obs, so it should actualize subset and not modify adata
    subset.obs.drop(columns=["oanno1"], inplace=True)
    assert not subset.is_view
    assert subset.obs.columns.tolist() == ["oanno2", "oanno3"]

    assert adata.obs.columns.tolist() == ["oanno1", "oanno2", "oanno3"]
def i1beta_phasor(up, i1, beta, r1, xd, xq, ax=0):
    """creates a phasor plot
    up: internal voltage
    i1: current
    beta: angle i1 vs up [deg]
    r1: resistance
    xd: reactance in direct axis
    xq: reactance in quadrature axis"""

    i1d, i1q = (i1*np.sin(beta/180*np.pi), i1*np.cos(beta/180*np.pi))
    uxdq = ((r1*i1d - xq*i1q), (r1*i1q + xd*i1d))
    __phasor_plot(ax, up, (i1d, i1q), uxdq)