重构第一版：重新验证2.0推荐写法

debug/syntax_app/dict_obj_app.py

@@ -0,0 +1,24 @@
+from datetime import datetime
+
+from pydantic import BaseModel
+
+
+class User(BaseModel):
+    id: int
+    name: str = "John Doe"
+    signup_ts: datetime | None = None
+    friends: list[int] = []
+
+
+external_data = {
+    "id": "123",
+    "signup_ts": "2017-06-01 12:22",
+    "friends": [1, "2", b"3"],
+}
+user = User(**external_data)
+print(user)
+# > User id=123 name='John Doe' signup_ts=datetime.datetime(2017, 6, 1, 12, 22) friends=[1, 2, 3]
+print(user.id)
+# > 123
+
+print(type(user.friends[0]),type(user.friends[1]),type(user.friends[2]))