automatic swagger documentation fails when multiple locations provided to regparser

[db0]

Code

class AsyncGenerate(Resource):
    parser = reqparse.RequestParser()
    parser.add_argument("prompt", type=str, required=True, help="The prompt to generate from")
    parser.add_argument("api_key", type=str, required=True, help="The API Key corresponding to a registered user", location=['headers', 'json'])
    parser.add_argument("params", type=dict, required=False, default={}, help="Extra generate params to send to the SD server")
    parser.add_argument("servers", type=str, action='append', required=False, default=[], help="If specified, only the server with this ID will be able to generate this prompt")
    @api.expect(parser)
    def post(self, api_version = None):

Expected Behavior

The swagger API should renger my regparser requirements correctly

Actual Behavior

If I set the location parameter of add_argument to a list of locations, the api.expect(parser) errors

Error Messages/Stack Trace

2022-09-22 16:44:58,743 - ERROR - api:576 - Unable to render schema
Traceback (most recent call last):
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\api.py", line 571, in __schema__
    self._schema = Swagger(self).as_dict()
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\swagger.py", line 239, in as_dict
    serialized = self.serialize_resource(
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\swagger.py", line 438, in serialize_resource
    doc = self.extract_resource_doc(resource, url, route_doc=route_doc)
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\swagger.py", line 343, in extract_resource_doc
    method_params = self.expected_params(method_doc)
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\swagger.py", line 382, in expected_params
    (p["name"], p) for p in expect.__schema__ if p["in"] != "body"
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\reqparse.py", line 435, in __schema__
    param = arg.__schema__
  File "C:\Users\Db0\AppData\Roaming\Python\Python310\site-packages\flask_restx\reqparse.py", line 290, in __schema__
    param = {"name": self.name, "in": LOCATIONS.get(self.location, "query")}
TypeError: unhashable type: 'list'

Environment

• Python version: 3.10.0
• Flask version: 2.1.3
• Flask-RESTX version: 0.5.1
• Other installed Flask extensions: flask_limiter