add AvgPooling layer

mindspore/nn/layer/pooling.py

@@ -268,13 +268,8 @@ class AvgPool1d(_PoolNd):
         ParamValidator.check_type('kernel_size', kernel_size, [int,])
         ParamValidator.check_type('stride', stride, [int,])
         self.pad_mode = ParamValidator.check_string('pad_mode', pad_mode.upper(), ['VALID', 'SAME'])
-        if not isinstance(kernel_size, int):
-            ParamValidator.check_integer("kernel_size", kernel_size, 1, Rel.GE)
-            raise ValueError("kernel_size should be 1 int number but got {}".
-                             format(kernel_size))
-        if not isinstance(stride, int):
-            ParamValidator.check_integer("stride", stride, 1, Rel.GE)
-            raise ValueError("stride should be 1 int number but got {}".format(stride))
+        ParamValidator.check_integer("kernel_size", kernel_size, 1, Rel.GE)
+        ParamValidator.check_integer("stride", stride, 1, Rel.GE)
         self.kernel_size = (1, kernel_size)
         self.stride = (1, stride)
         self.avg_pool = P.AvgPool(ksize=self.kernel_size,