[Python] How should I specify default values on Pydantic fields with "Validate Always" to...

My type checker moans at me when I use snippets like this one from the Pydantic docs:

from datetime import datetime

from pydantic import BaseModel, validator


class DemoModel(BaseModel):
ts: datetime = None # Expression of type "None" cannot be
# assigned to declared type "datetime"

@validator('ts', pre=True, always=True)
def set_ts_now(cls, v):
return v or datetime.now()


My workarounds so far have been:

ts: datetime = datetime(1970, 1, 1) # yuck


ts: datetime = None # type: ignore


ts: Optional[datetime] = None # Not really true. `ts` is not optional.


Is there a preferred way out of this conundrum?

Or is there a type checker I could use which doesn't mind this?

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