How can I use the Salesforce Bulk API from Python to set a date field in Salesforce to be empty/null for multiple records in a bulk operation?

I have tried with following

None - request accepted and got success response, but in the salesforce UI still the field holds the date. Other string fields got updated which I sent through that request
"" - Same as None this empty quotes also accepted but not reflected in UI
'null' - request accepted but error response as the date field will not accept '/null'/
"0001-01-01" - request accepted but error response as the date field will not accept this date

So is there a way in salesforce bulk api to clear a date field which already holds a date?