solve circular imports

csst_dag/dag/__init__.py

 from ._base_dag import BaseDAG, Level1DAG, Level2DAG
 from ._dispatcher import Dispatcher
 from .._csst import csst
-from ._dag_utils import generate_permutations
+from ..dag_utils import generate_permutations
 
 CSST_DAGS = {
     # MSC

csst_dag/dag/_base_dag.py

@@ -5,13 +5,13 @@ from typing import Callable, Optional
 import yaml
 from astropy import table, time
 
-from ._dag_utils import (
+from ._dispatcher import Dispatcher
+from ..dag_utils import (
     force_string,
     override_common_keys,
     generate_sha1_from_time,
 )
 from ..dfs import DFS
-from ._dispatcher import Dispatcher
 
 DAG_CONFIG_DIR = os.path.join(
     os.path.dirname(os.path.dirname(__file__)),

csst_dag/dfs.py

 import os
-from astropy import table
 import socket
-from typing import Optional
 from urllib.parse import urlparse
 
 import csst_fs
-import numpy as np
 from astropy import table
 from csst_dfs_client import plan, level0, level1, catalog
 
 from ._csst import csst
-from .dag._dag_utils import override_common_keys
-
+from .dag_utils import override_common_keys
 
 # -----------------
 # INPUT PARAMETERS