def test_view_of_view(matrix_type, subset_func, subset_func2):
    adata = gen_adata((30, 15), X_type=matrix_type)
    adata.raw = adata
    if subset_func is single_subset:
        pytest.xfail("Other subset generating functions have trouble with this")
    var_s1 = subset_func(adata.var_names, min_size=4)
    var_view1 = adata[:, var_s1]
    var_s2 = subset_func2(var_view1.var_names)
    var_view2 = var_view1[:, var_s2]
    assert var_view2._adata_ref is adata
    obs_s1 = subset_func(adata.obs_names, min_size=4)
    obs_view1 = adata[obs_s1, :]
    obs_s2 = subset_func2(obs_view1.obs_names)
    assert adata[obs_s1, :][:, var_s1][obs_s2, :]._adata_ref is adata

    view_of_actual_copy = adata[:, var_s1].copy()[obs_s1, :].copy()[:, var_s2].copy()

    view_of_view_copy = adata[:, var_s1][obs_s1, :][:, var_s2].copy()

    assert_equal(view_of_actual_copy, view_of_view_copy, exact=True)
def get_namespace(
        self, namespace: str, lowercase: bool = True, trim_namespace: bool = True
    ) -> t.Dict[str, t.Any]:
        """Returns a dictionary containing a subset of configuration options
        that match the specified namespace/prefix. Example usage::

            app.config['IMAGE_STORE_TYPE'] = 'fs'
            app.config['IMAGE_STORE_PATH'] = '/var/app/images'
            app.config['IMAGE_STORE_BASE_URL'] = 'http://img.website.com'
            image_store_config = app.config.get_namespace('IMAGE_STORE_')

        The resulting dictionary `image_store_config` would look like::

            {
                'type': 'fs',
                'path': '/var/app/images',
                'base_url': 'http://img.website.com'
            }

        This is often useful when configuration options map directly to
        keyword arguments in functions or class constructors.

        :param namespace: a configuration namespace
        :param lowercase: a flag indicating if the keys of the resulting
                          dictionary should be lowercase
        :param trim_namespace: a flag indicating if the keys of the resulting
                          dictionary should not include the namespace

        .. versionadded:: 0.11
        """
        rv = {}
        for k, v in self.items():
            if not k.startswith(namespace):
                continue
            if trim_namespace:
                key = k[len(namespace) :]
            else:
                key = k
            if lowercase:
                key = key.lower()
            rv[key] = v
        return rv