Fixing TabError

trello/board.py", line 222
    arguments["display/cardFront"] = u"true" if display_on_card else u"false"
                                                                            ^
TabError: inconsistent use of tabs and spaces in indentation

trello/board.py

@@ -219,7 +219,7 @@ def update_custom_field_definition(self, custom_field_definition_id, name=None,
 		if name:
 			arguments["name"] = name
 		if not display_on_card is None:
-        	arguments["display/cardFront"] = u"true" if display_on_card else u"false"
+			arguments["display/cardFront"] = u"true" if display_on_card else u"false"
 		if pos:
 			arguments["pos"] = pos
 
@@ -520,6 +520,8 @@ def get_power_ups(self, board_id=None, name='', filters=None):
 		if board_id is None:
 			board_id = self.id
 		if filters:
+			if not filters in ("enabled", "available"):
+				filers = "enabled"
 			arguments['filter'] = filters
 		json_obj = self.client.fetch_json(
 			'/boards/' + board_id +'/plugins',