Upgrade No. 8 to Pydantic v2

README.md

@@ -416,16 +416,11 @@ Having a controllable global base model allows us to customize all the models wi
 For example, we could have a standard datetime format or add a super method for all subclasses of the base model.
 ```python
 from datetime import datetime
+from typing import Any
 from zoneinfo import ZoneInfo
 
-import orjson
 from fastapi.encoders import jsonable_encoder
-from pydantic import BaseModel, root_validator
-
-
-def orjson_dumps(v, *, default):
-    # orjson.dumps returns bytes, to match standard json.dumps we need to decode
-    return orjson.dumps(v, default=default).decode()
+from pydantic import BaseModel, ConfigDict, model_validator
 
 
 def convert_datetime_to_gmt(dt: datetime) -> str:
@@ -435,15 +430,15 @@ def convert_datetime_to_gmt(dt: datetime) -> str:
     return dt.strftime("%Y-%m-%dT%H:%M:%S%z")
 
 
-class ORJSONModel(BaseModel):
-    class Config:
-        json_loads = orjson.loads
-        json_dumps = orjson_dumps
-        json_encoders = {datetime: convert_datetime_to_gmt}  # method for customer JSON encoding of datetime fields
+class CustomModel(BaseModel):
+    model_config = ConfigDict(
+        json_encoders={datetime: convert_datetime_to_gmt},
+        populate_by_name=True,
+    )
 
-    @root_validator()
-    def set_null_microseconds(cls, data: dict) -> dict:
-       """Drops microseconds in all the datetime field values."""
+    @model_validator(mode="before")
+    @classmethod
+    def set_null_microseconds(cls, data: dict[str, Any]) -> dict[str, Any]:
         datetime_fields = {
             k: v.replace(microsecond=0)
             for k, v in data.items()
@@ -453,10 +448,11 @@ class ORJSONModel(BaseModel):
         return {**data, **datetime_fields}
 
     def serializable_dict(self, **kwargs):
-       """Return a dict which contains only serializable fields."""
-        default_dict = super().dict(**kwargs)
+        """Return a dict which contains only serializable fields."""
+        default_dict = self.model_dump()
 
         return jsonable_encoder(default_dict)
+
 ```
 In the example above we have decided to make a global base model which: 
 - uses [orjson](https://github.com/ijl/orjson) to serialize data