Unpacking str dict value into datetime attribute of an object in a nice way

I have a pydantic class like

class MyClass(BaseModel):
    base: str
    success: bool
    date: datetime

I also have a dict like

dict = {
    "base": "abc",
    "success": True,
    "date": "2023-04-30"
}

So I want to do something like obj = MyClass(**dict) but also convert str "date" from dict into datetime "date" of the obj automatically

How to do that in a clean and nice way?

>Solution :

Use a validator to transform the value before it gets assigned to the date field. In the follow code will transform the date into a format supported by Pydantic:

from pydantic import BaseModel, validator
from datetime import datetime

class MyClass(BaseModel):
    base: str
    success: bool
    date: datetime

    @validator('date', pre=True)
    def validate_date(cls, v):
        return f'{v}T00:00'


example = MyClass(**{
    "base": "abc",
    "success": True,
    "date": "2023-04-30"
})

print(example)

Running the above code will output:

base='abc' success=True date=datetime.datetime(2023, 4, 30, 0, 0)