Refine type hint and recorder (#1248)

* Refine type hint and recorder

* log environment automatically

* Add literal annotation

* fix type hint bug 3.7

qlib/typehint.py

@@ -4,6 +4,8 @@
 """Commonly used types."""
 
 import sys
+from typing import Union
+from pathlib import Path
 
 __all__ = ["Literal", "TypedDict", "final"]
 
@@ -11,3 +13,51 @@ if sys.version_info >= (3, 8):
     from typing import Literal, TypedDict, final  # type: ignore  # pylint: disable=no-name-in-module
 else:
     from typing_extensions import Literal, TypedDict, final
+
+
+class InstDictConf(TypedDict):
+    """
+    InstDictConf  is a Dict-based config to describe an instance
+
+        case 1)
+        {
+            'class': 'ClassName',
+            'kwargs': dict, #  It is optional. {} will be used if not given
+            'model_path': path, # It is optional if module is given in the class
+        }
+        case 2)
+        {
+            'class': <The class it self>,
+            'kwargs': dict, #  It is optional. {} will be used if not given
+        }
+    """
+
+    # class: str  # because class is a keyword of Python. We have to comment it
+    kwargs: dict  # It is optional. {} will be used if not given
+    module_path: str  # It is optional if module is given in the class
+
+
+InstConf = Union[InstDictConf, str, object, Path]
+"""
+InstConf is a type to describe an instance; it will be passed into init_instance_by_config for Qlib
+
+    config : Union[str, dict, object, Path]
+
+        InstDictConf example.
+            please refer to the docs of InstDictConf
+
+        str example.
+            1) specify a pickle object
+                - path like 'file:///<path to pickle file>/obj.pkl'
+            2) specify a class name
+                - "ClassName":  getattr(module, "ClassName")() will be used.
+            3) specify module path with class name
+                - "a.b.c.ClassName" getattr(<a.b.c.module>, "ClassName")() will be used.
+
+        object example:
+            instance of accept_types
+
+        Path example:
+            specify a pickle object
+                - it will be treated like 'file:///<path to pickle file>/obj.pkl'
+"""