[Bug] fix raise error bug in registering multiple names (#949)

* fix raise error bug in registering multiple names

* fix bug in checking the type of name

* fix lint

* fix unit test for registry

* fix bug in unit test

mmcv/utils/registry.py

@@ -239,11 +239,6 @@ class Registry:
             module_name = module_class.__name__
         if isinstance(module_name, str):
             module_name = [module_name]
-        else:
-            assert is_seq_of(
-                module_name,
-                str), ('module_name should be either of None, an '
-                       f'instance of str or list, but got {type(module_name)}')
         for name in module_name:
             if not force and name in self._module_dict:
                 raise KeyError(f'{name} is already registered '
@@ -297,16 +292,18 @@ class Registry:
         if isinstance(name, type):
             return self.deprecated_register_module(name, force=force)
 
+        # raise the error ahead of time
+        if not (name is None or isinstance(name, str) or is_seq_of(name, str)):
+            raise TypeError(
+                'name must be either of None, an instance of str or a sequence'
+                f'  of str, but got {type(name)}')
+
         # use it as a normal method: x.register_module(module=SomeClass)
         if module is not None:
             self._register_module(
                 module_class=module, module_name=name, force=force)
             return module
 
-        # raise the error ahead of time
-        if not (name is None or isinstance(name, str)):
-            raise TypeError(f'name must be a str, but got {type(name)}')
-
         # use it as a decorator: @x.register_module()
         def _register(cls):
             self._register_module(

tests/test_utils/test_registry.py

@@ -46,11 +46,12 @@ def test_registry():
     assert CATS.get('PersianCat') is None
     assert 'PersianCat' not in CATS
 
-    @CATS.register_module(name='Siamese')
+    @CATS.register_module(name=['Siamese', 'Siamese2'])
     class SiameseCat:
         pass
 
     assert CATS.get('Siamese').__name__ == 'SiameseCat'
+    assert CATS.get('Siamese2').__name__ == 'SiameseCat'
 
     class SphynxCat:
         pass
@@ -68,6 +69,8 @@ def test_registry():
                  "<locals>.Munchkin'>, ")
     repr_str += ("'Siamese': <class 'test_registry.test_registry."
                  "<locals>.SiameseCat'>, ")
+    repr_str += ("'Siamese2': <class 'test_registry.test_registry."
+                 "<locals>.SiameseCat'>, ")
     repr_str += ("'Sphynx': <class 'test_registry.test_registry."
                  "<locals>.SphynxCat'>, ")
     repr_str += ("'Sphynx1': <class 'test_registry.test_registry."
@@ -78,7 +81,7 @@ def test_registry():
     assert repr(CATS) == repr_str
 
     # name type
-    with pytest.raises(AssertionError):
+    with pytest.raises(TypeError):
         CATS.register_module(name=7474741, module=SphynxCat)
 
     # the registered module should be a class