TypeError when query is empty

[realflash]

When I carry out a query without filters, such as:

board.get_cards()

I get this error below. Putting in a query gets rid of this error.

Traceback (most recent call last):
  File "./test.py", line 22, in <module>
    cards = source_board.get_cards()
  File "/usr/local/lib/python2.7/dist-packages/trello/__init__.py", line 345, in get_cards
    query_params=filters
  File "/usr/local/lib/python2.7/dist-packages/trello/__init__.py", line 156, in fetch_json
    url = self.build_url(uri_path, query_params)
  File "/usr/local/lib/python2.7/dist-packages/trello/__init__.py", line 106, in build_url
    if len(query) > 0:
TypeError: object of type 'NoneType' has no len()