[BUG] [Python] _headers is not initialized properly for delete functions

Created by: Santobert

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Description

When deleting objects using the new python generator, an error occurs in api_client.py update_params_for_auth():

AttributeError: 'dict' object has no attribute 'add'

This error can be traced back to the paths/{my api}/delete.py file, where the following line is missing unlike the other files (get.py, put.py, ...):

        _headers = HTTPHeaderDict()

This results in the variable headers becoming an empty dict in api_client.py __call_api():

        headers = headers or {}

openapi-generator version

6.2.0

OpenAPI declaration file content or url

Generation Details

java -jar openapi-generator-cli-6.2.0.jar generate -i openapi.yaml -g python -o python

Steps to reproduce

Related issues/PRs

Suggest a fix

Either the missing line needs to be added to delete.py: https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/python/endpoint.handlebars#L316

or the headers should be initialized as HTTPHeaderDict