[Typing][B-89] Add type annotations for `python/paddle/nn/utils/weigh…

…t_norm_hook.py` (#65812)

python/paddle/nn/utils/weight_norm_hook.py

@@ -11,17 +11,30 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
 import paddle
 from paddle import _C_ops
 
 from ...base.data_feeder import check_variable_and_dtype
 from ...base.layer_helper import LayerHelper
 from ...framework import in_dynamic_mode
 
+if TYPE_CHECKING:
+    from typing_extensions import Never
+
+    from paddle import Tensor
+    from paddle.nn import Layer
+
 __all__ = []
 
 
-def l2_norm(x, axis, epsilon=1e-12, name=None):
+def l2_norm(
+    x: Tensor, axis: int, epsilon: float = 1e-12, name: str | None = None
+) -> Tensor:
     if len(x.shape) == 1:
         axis = 0
 
@@ -46,7 +59,7 @@ def l2_norm(x, axis, epsilon=1e-12, name=None):
     return paddle.squeeze(norm, axis=[axis])
 
 
-def norm_except_dim(p, dim):
+def norm_except_dim(p: Tensor, dim: int) -> Tensor:
     shape = p.shape
     ndims = len(shape)
     if dim == -1:
@@ -65,7 +78,7 @@ def norm_except_dim(p, dim):
         return norm_except_dim(p_transposed, 0)
 
 
-def _weight_norm(v, g, dim):
+def _weight_norm(v: Tensor, g: Tensor, dim: int) -> Tensor:
     shape = v.shape
     ndims = len(shape)
 
@@ -96,19 +109,22 @@ def _weight_norm(v, g, dim):
 
 
 class WeightNorm:
-    def __init__(self, name, dim):
+    name: str
+    dim: int
+
+    def __init__(self, name: str, dim: int) -> None:
         if dim is None:
             dim = -1
         self.name = name
         self.dim = dim
 
-    def compute_weight(self, layer):
+    def compute_weight(self, layer: Layer) -> Tensor:
         g = getattr(layer, self.name + '_g')
         v = getattr(layer, self.name + '_v')
         return _weight_norm(v, g, self.dim)
 
     @staticmethod
-    def apply(layer, name, dim):
+    def apply(layer: Layer, name: str, dim: int) -> WeightNorm:
         for k, hook in layer._forward_pre_hooks.items():
             if isinstance(hook, WeightNorm) and hook.name == name:
                 raise RuntimeError(
@@ -145,7 +161,7 @@ def apply(layer, name, dim):
         layer.register_forward_pre_hook(fn)
         return fn
 
-    def remove(self, layer):
+    def remove(self, layer: Layer) -> None:
         w_var = self.compute_weight(layer)
         delattr(layer, self.name)
         del layer._parameters[self.name + '_g']
@@ -155,11 +171,11 @@ def remove(self, layer):
         with paddle.no_grad():
             paddle.assign(w_var, w)
 
-    def __call__(self, layer, inputs):
+    def __call__(self, layer: Layer, inputs: Never) -> None:
         setattr(layer, self.name, self.compute_weight(layer))
 
 
-def weight_norm(layer, name='weight', dim=0):
+def weight_norm(layer: Layer, name: str = 'weight', dim: int = 0) -> Layer:
     r"""
     Applies weight normalization to a parameter according to the
     following formula:
@@ -205,7 +221,7 @@ def weight_norm(layer, name='weight', dim=0):
     return layer
 
 
-def remove_weight_norm(layer, name='weight'):
+def remove_weight_norm(layer: Layer, name: str = 'weight') -> Layer:
     """
     remove weight normalization from layer.