Fix balances returning.

accountant/views/accounts.py

@@ -7,7 +7,7 @@ import dateutil.parser
 from flask_jwt_extended import jwt_required
 from flask_restplus import Namespace, Resource, fields
 
-from ..models import db
+from ..models import db, row_as_dict
 from ..models.accounts import Account
 from ..models.operations import Operation
 
@@ -268,7 +268,9 @@ class BalancesResource(Resource):
 
         # Note: if we don't pass the code, the result is seen as a tuple and
         # causes error on marshalling.
-        return account.balances(), 200
+        return row_as_dict(
+            account.balances()
+        ), 200
 
 
 @ns.route('/<int:account_id>/balance')