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 _make_proxy(self, key, match):
        proxy_type = match.group("type")
        key = match.group("key").strip()
        if proxy_type == "env":
            proxy = EnvProxy(key)
        else:
            proxy = ResolverMethodProxy(self._resolver, proxy_type, key)
        filters = [f for f in [rf.strip() for rf in match.group("filters").split("|")] if f]
        for filter_name in filters:
            if filter_name == "jsondecode":
                proxy = JSONDecodeFilter(proxy)
            elif filter_name == "base64decode":
                proxy = Base64DecodeFilter(proxy)
            elif filter_name.startswith("element:"):
                key = filter_name.split(":", 1)[-1]
                proxy = ElementFilter(key, proxy)
            else:
                raise ValueError("Unknown filter %s", filter_name)
        return proxy