[BUG][PYTHON] data-time format returning datetime obj (datetime.datetime(2017, 1, 2, 6, 24, 17, tzinfo=TzInfo(UTC)))) instead of ISO format

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• [y] Have you validated the input using an OpenAPI validator (example)?
• [y] Have you tested with the latest master to confirm the issue still exists?
• [y] Have you searched for related issues/PRs?
• [y] What's the actual output vs expected output?
  Actual Output: date_time_end=datetime.datetime(2017, 1, 2, 6, 24, 17, tzinfo=TzInfo(UTC)))
Expected Output: '2017-07-21T17:32:28Z'
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

OpenAPI Generator is not formatting date-time properties as expected in the generated code.
You've specified the format "date-time" with "format: date-time" in the schema, but the output is a datetime object instead of the desired ISO 8601 string format ('YYYY-MM-DDTHH:MM:SSZ')..

openapi-generator version

which version of openapi-generator are you using, is it a regression? v7.4.0

OpenAPI declaration file content or url

dateTimeEnd:
          type: string
          format: date-time

Generation Details

docker run --rm \
-v ${PWD}:/local openapitools/openapi-generator-cli:v7.4.0 generate \
-i  /local/products.yaml \
--package-name productsapi_client \
-g python \
-o /local/python/productsapi_client
cd python/productsapi_client
poetry add parameterized

Tried adding the additional-properties=datetimeFormat=%Y-%m-%dT%H:%M:%SZ flag.

Steps to reproduce

The API response on swagger docs returns this format - %Y-%m-%dT%H:%M:%S%z
Whereas if I create client by schema docs from same API swagger page then client returns - datetime.datetime(2017, 1, 2, 6, 24, 17, tzinfo=TzInfo(UTC)))

Related issues/PRs

https://github.com/OpenAPITools/openapi-generator/issues/16284
https://github.com/britned/empire-platform-api/issues/4
https://github.com/OpenAPITools/openapi-generator/issues/14503

Suggest a fix

When I am changing my products.yaml to

        dateTimeEnd:
          type: string
          format: '^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}\.[0-9]{3}Z$'

then it seems to work but format: date-time should also work fine.

Start with the products.yaml schema and the generated Python client produced by the documented v7.4.0 Docker command. Reproduce the date-time response using the provided schema, then trace where the client handles the date-time field and compare the returned datetime object with the expected ISO 8601 string. Done means format: date-time produces the expected string without requiring a regex workaround.