I get 401 status code and this error if I try to use more than one filter parameters:

{u'errors': [{u'message': u'Invalid Signature - provided signature does not match', u'code': u'woocommerce_api_authentication_error'}]}

I'm using v3.

One parameter works well:

api.get('orders?filter[limit]=1000')
api.get('orders?filter[created_at_min]=2015-01-03')

But there is an Invalid Signature error for multiple filter params:

api.get('orders?filter[limit]=1000&filter[created_at_min]=2015-01-03')

The example from the REST API docs is failing too:

api.get('orders?status=completed&filter[created_at_min]=2013-11-01&filter[created_at_max]=2013-11-30')

Am I doing something wrong? Or is there a bug in the generate_oauth_signature method?