fix doc problems

mindspore/nn/layer/normalization.py

@@ -17,6 +17,7 @@ from mindspore.ops import operations as P
 from mindspore.ops import functional as F
 from mindspore.common.parameter import Parameter
 from mindspore.common.initializer import initializer
+from mindspore.ops.primitive import constexpr
 from mindspore.common.tensor import Tensor
 import mindspore.common.dtype as mstype
 import mindspore.context as context
@@ -165,7 +166,9 @@ class _BatchNorm(Cell):
     def extend_repr(self):
         return 'num_features={}, eps={}, momentum={}, gamma={}, beta={}, moving_mean={}, moving_variance={}'.format(
             self.num_features, self.eps, self.momentum, self.gamma, self.beta, self.moving_mean, self.moving_variance)
-
+def _channel_check(channel, num_channel):
+    if channel != num_channel:
+        raise ValueError("the input channel is not equal with num_channels")
 
 class BatchNorm1d(_BatchNorm):
     r"""
@@ -508,6 +511,7 @@ class GroupNorm(Cell):
 
     def construct(self, x):
         batch, channel, height, width = self.shape(x)
+        _channel_check(channel, self.num_channels)
         x = self.reshape(x, (batch, self.num_groups, channel*height*width/self.num_groups))
         mean = self.reduce_mean(x, 2)
         var = self.reduce_sum(self.square(x - mean), 2) / (channel * height * width / self.num_groups - 1)