[python] Bug - Duplicated required params when generating python client with parameters in : body

Description

Using parameters/in/body in swagger 2.0 generating python client with swagger-codegen 3.0.22 creates a client with an extra required parameter body and "parameter name".

No matter if you specify one or both parameters, the client call fails.

Swagger-codegen version

3.0.22

Swagger declaration file content or url

https://gist.github.com/albertsola/5dd4d84cfbcb7c45d4585dcde75f26b1

"paths": {
    "/call": {
      "post": {
          "parameters": [
              {
                  "name": "uuid",
                  "in": "body",
                  "required": true,
                  "schema": {
                    "$ref": "#/definitions/RequestObject"
                  }
            }
        ]
    }
}

Command line used for generation

swagger-codegen generate -l python -i bug.json -DpackageName=bug_api -o packages/bug_api

Steps to reproduce

1. Generate the client
2. Code generated has what looks like a bug:

def buggy_method(self, body, uuid, **kwargs):  # noqa: E501
    [...]
    if kwargs.get('async_req'):
        return self.buggy_method_with_http_info(body, uuid, **kwargs)  # noqa: E501
    else:
        (data) = self.buggy_method_with_http_info(body, uuid, **kwargs)  # noqa: E501
        return data

def buggy_method_with_http_info(self, body, uuid, **kwargs):  # noqa: E501
    [...]
    if ('body' not in params or
            params['body'] is None):
            raise ValueError("Missing the required parameter `body` when calling `buggy_method`")  # noqa: E501
    # verify the required parameter 'uuid' is set
    if ('uuid' not in params or
            params['uuid'] is None):
            raise ValueError("Missing the required parameter `uuid` when calling `buggy_method`")  # noqa: E501
    [...]
    form_params = []
    local_var_files = {}
    if 'uuid' in params:
        form_params.append(('uuid', params['uuid']))  # noqa: E501

    body_params = None
    if 'body' in params:
        body_params = params['body']
    [...]
    return self.api_client.call_api(
          '/call', 'POST',
          path_params,
          query_params,
          header_params,
          body=body_params,
          post_params=form_params,
          files=local_var_files,
          response_type='ResponseObject',  # noqa: E501
          auth_settings=auth_settings,
          async_req=params.get('async_req'),
          _return_http_data_only=params.get('_return_http_data_only'),
          _preload_content=params.get('_preload_content', True),
          _request_timeout=params.get('_request_timeout'),
          collection_formats=collection_formats)

both body and uuid paramaters are required.

If you use only one parameter (body=None, uuid=valid-uuid) or (body={json}, uuid=None), API client raise a required parameter is missing.

ValueError: Missing the required parameter `body` when calling ...

If you use both:

ValueError: body parameter cannot be used with post_params parameter.

Related issues/PRs

Not found.

Suggest a fix/enhancement

@todo / Open for suggestions.

Reproduce the issue with the provided Swagger declaration and the swagger-codegen Python generation command. Inspect the generated buggy_method and buggy_method_with_http_info handling of the body and uuid parameters; done means the generated client no longer duplicates required parameters and valid body-only, uuid-only, and combined calls behave correctly.