How do I use/document a GET parameter in flask-apispec?

I have GET parameters I would like to use/document with apispec.

Example: I have the GET parameter **color** so I do requests like

`GET /pets?color=black`

```
@app.route('/pets')
@use_kwargs({'category': fields.Str(), 'size': fields.Str()})
@marshal_with(PetSchema(many=True))
def get_pets(**kwargs):
color=request.args.get('color', None)
return Pet.query.filter_by(**kwargs, color)

```

How do I declare **color** GET parameter in flask-apispec?