Support and test passing a dict as first argument to change_flags

tests/test_config.py

@@ -158,6 +158,9 @@ def test_config_context():
 
     with configparser.change_flags(test_config_context="new_value"):
         assert root.test_config_context == "new_value"
+        with root.change_flags({"test_config_context": "new_value2"}):
+            assert root.test_config_context == "new_value2"
+        assert root.test_config_context == "new_value"
     assert root.test_config_context == "test_default"
 
 

theano/configparser.py

@@ -23,10 +23,11 @@ class TheanoConfigWarning(Warning):
 class _ChangeFlagsDecorator:
     def __init__(self, *args, _root=None, **kwargs):
         # the old API supported passing a dict as the first argument:
-        args = dict(args)
-        args.update(kwargs)
-        self.confs = {k: _root._config_var_dict[k] for k in args}
-        self.new_vals = args
+        if args:
+            assert len(args) == 1 and isinstance(args[0], dict)
+            kwargs = dict(**args[0], **kwargs)
+        self.confs = {k: _root._config_var_dict[k] for k in kwargs}
+        self.new_vals = kwargs
         self._root = _root
 
     def __call__(self, f):