def get(self, version):
        """Endpoint that renders an OpenApi spec for all views that belong
            to a certain version
        ---
        get:
          description: >-
            Get the OpenAPI spec for a specific API version
          parameters:
          - in: path
            schema:
              type: string
            name: version
          responses:
            200:
              description: The OpenAPI spec
              content:
                application/json:
                  schema:
                    type: object
            404:
              $ref: '#/components/responses/404'
            500:
              $ref: '#/components/responses/500'
        """
        version_found = False
        api_spec = self._create_api_spec(version)
        for base_api in current_app.appbuilder.baseviews:
            if isinstance(base_api, BaseApi) and base_api.version == version:
                base_api.add_api_spec(api_spec)
                version_found = True
        if version_found:
            return self.response(200, **api_spec.to_dict())
        else:
            return self.response_404()
Endpoint that renders an OpenApi spec for all views that belong
            to a certain version
        ---
        get:
          description: >-
            Get the OpenAPI spec for a specific API version
          parameters:
          - in: path
            schema:
              type: string
            name: version
          responses:
            200:
              description: The OpenAPI spec
              content:
                application/json:
                  schema:
                    type: object
            404:
              $ref: '#/components/responses/404'
            500:
              $ref: '#/components/responses/500'
        
flask_appbuilder/api/manager.py