Conflict between the filtering operations' description and ability to take empty values

[theophile-scrive]

When reading the code for autoFilterDesc, I read the following:

"NB: Specifying filtering operation is mandatory for this parameter!"

(line 75)

However I also read in filterOpenApiParam the following:

O._paramAllowEmptyValue = Just True

(line 45)

From a cursory look this looks like a contradiction. Is there a reasoning for it? I can submit a fix if you wish to change either the description or the OpenAPI (and Swagger) documentation.