fix: can't implement len for KerasShapesWrapper & Add bias implement to Conv2DTranspose.Call()

Author: lingbai-kong

src/TensorFlowNET.Keras/Layers/Convolution/Conv2DTranspose.cs

@@ -62,7 +62,7 @@ private static Conv2DArgs InitializeUndefinedArgs(Conv2DArgs args)
         public override void build(KerasShapesWrapper input_shape)
         {
             var single_shape = input_shape.ToSingleShape();
-            if (len(input_shape) != 4)
+            if (len(single_shape) != 4)
                 throw new ValueError($"Inputs should have rank 4. Received input shape: {input_shape}");
 
             var channel_axis = _get_channel_axis();
@@ -138,7 +138,10 @@ protected override Tensors Call(Tensors inputs, Tensor state = null, bool? train
             }
 
             if (use_bias)
-                throw new NotImplementedException("");
+                tf.nn.bias_add(
+                    outputs,
+                    bias,
+                    data_format: conv_utils.convert_data_format(data_format, ndim: 4));
 
             if (activation != null)
                 return activation.Apply(outputs);