add contains to registry (#223)

* add contains to registry
Signed-off-by: lixuanyi <lixuanyi@sensetime.com>

* add contains to registry

* 'fix'

* 'minor'

* move
Signed-off-by: lixuanyi <lixuanyi@sensetime.com>
Co-authored-by: lixuanyi <lixuanyi@sensetime.com>

mmcv/utils/registry.py

@@ -18,6 +18,9 @@ class Registry(object):
     def __len__(self):
         return len(self._module_dict)
 
+    def __contains__(self, key):
+        return self.get(key) is not None
+
     def __repr__(self):
         format_str = self.__class__.__name__ + '(name={}, items={})'.format(
             self._name, list(self._module_dict.keys()))

tests/test_registry.py

@@ -23,6 +23,7 @@ def test_registry():
     CATS.register_module(Munchkin)
     assert len(CATS) == 2
     assert CATS.get('Munchkin') is Munchkin
+    assert 'Munchkin' in CATS
 
     with pytest.raises(KeyError):
         CATS.register_module(Munchkin)
@@ -43,6 +44,7 @@ def test_registry():
     assert len(CATS) == 2
 
     assert CATS.get('PersianCat') is None
+    assert 'PersianCat' not in CATS
 
     # The order of dict keys are not preserved in python 3.5
     assert repr(CATS) in [