add docs

qlib/workflow/task/manage.py

@@ -24,7 +24,9 @@ from bson.binary import Binary
 from bson.objectid import ObjectId
 from pymongo.errors import InvalidDocument
 from qlib import auto_init, get_module_logger
+import qlib
 from tqdm.cli import tqdm
+import yaml
 
 from .utils import get_mongodb
 
@@ -72,24 +74,26 @@ class TaskManager:
     def __init__(self, task_pool: str):
         """
         Init Task Manager, remember to make the statement of MongoDB url and database name firstly.
+        A TaskManager instance serves a specific task pool.
+        The static method of this module serves the whole MongoDB.
 
         Parameters
         ----------
         task_pool: str
             the name of Collection in MongoDB
         """
-        self.mdb = get_mongodb()
-        self.task_pool = getattr(self.mdb, task_pool)
+        self.task_pool = getattr(get_mongodb(), task_pool)
         self.logger = get_module_logger(self.__class__.__name__)
 
-    def list(self) -> list:
+    @staticmethod
+    def list() -> list:
         """
-        List the all collection(task_pool) of the db
+        List the all collection(task_pool) of the db.
 
         Returns:
             list
         """
-        return self.mdb.list_collection_names()
+        return get_mongodb().list_collection_names()
 
     def _encode_task(self, task):
         for prefix in self.ENCODE_FIELDS_PREFIX:
@@ -109,6 +113,16 @@ class TaskManager:
         return {k: str(v) for k, v in flt.items()}
 
     def _decode_query(self, query):
+        """
+        If the query includes any `_id`, then it needs `ObjectId` to decode.
+        For example, when using TrainerRM, it needs query `{"_id": {"$in": _id_list}}`. Then we need to `ObjectId` every `_id` in `_id_list`.
+
+        Args:
+            query (dict): query dict. Defaults to {}.
+
+        Returns:
+            dict: the query after decoding.
+        """
         if "_id" in query:
             if isinstance(query["_id"], dict):
                 for key in query["_id"]: