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 get_initial_verification(cls, user, earliest_allowed_date=None):
        """Get initial verification for a user with the 'photo_id_key'.

        Arguments:
            user(User): user object
            earliest_allowed_date(datetime): override expiration date for initial verification

        Return:
            SoftwareSecurePhotoVerification (object) or None
        """
        init_verification = cls.objects.filter(
            user=user,
            status__in=["submitted", "approved"],
            created_at__gte=(
                earliest_allowed_date or earliest_allowed_verification_date()
            )
        ).exclude(photo_id_key='')

        return init_verification.latest('created_at') if init_verification.exists() else None