When processing primitive types look for the 'format' field and if can add getters/setters that enforce this/use appropriate php types

[SDParish]

See https://swagger.io/specification/v2/#data-types for information on the format field.
Note that format is both optional, and can be any string, so if not found or recognised, will need to gracefully ignore.

Specifically, where format is date/date-time the model could enforce that set strings are in the required format, and could also allow setting from a DateTimeInterface, or allow getting as a DateTimeImmutable or DateTime.