diff --git a/src/TensorFlowNET.Core/Gradients/gradients_util.cs b/src/TensorFlowNET.Core/Gradients/gradients_util.cs
index 3b6d0eea..5aa0d044 100644
--- a/src/TensorFlowNET.Core/Gradients/gradients_util.cs
+++ b/src/TensorFlowNET.Core/Gradients/gradients_util.cs
@@ -61,7 +61,7 @@ namespace Tensorflow
                     string grad_scope = scope;
                     // Get a uid for this call to gradients that can be used to help
                     // cluster ops for compilation.
-                    var gradient_uid = ops.get_default_graph().unique_name("uid");
+                    var gradient_uid = curr_graph.unique_name("uid");
                     ys = ops.convert_n_to_tensor_or_indexed_slices(ys, name: "y");
                     xs = ops.internal_convert_n_to_tensor_or_indexed_slices(xs, name: "x", as_ref: true);
                     grad_ys = _DefaultGradYs(grad_ys, ys, colocate_gradients_with_ops, gradient_uid);
@@ -80,7 +80,7 @@ namespace Tensorflow
                     var to_ops = ys.Select(x => x.op).ToList();
                     var from_ops = xs.Select(x => x.op).ToList();
                     var stop_gradient_ops = stop_gradients.Select(x => x.op).ToList();
-                    (var reachable_to_ops, var pending_count, var loop_state) = _PendingCount(to_ops, from_ops, colocate_gradients_with_ops, new List<object>(), xs);
+                    var (reachable_to_ops, pending_count, loop_state) = _PendingCount(to_ops, from_ops, colocate_gradients_with_ops, new List<object>(), xs);
 
                     foreach (var (y, grad_y) in zip(ys, grad_ys))
                         _SetGrad(grads, y, grad_y);
@@ -168,7 +168,7 @@ namespace Tensorflow
                         {
                             if (in_grad != null)
                             {
-                                if (in_grad is Tensor &&
+                                if (!(in_grad is null) &&
                                     in_grad.Tag == null && // maybe a IndexedSlice
                                     t_in.dtype != TF_DataType.TF_RESOURCE)
                                 {
diff --git a/test/TensorFlowNET.UnitTest/TensorFlowNET.UnitTest.csproj.DotSettings b/test/TensorFlowNET.UnitTest/TensorFlowNET.UnitTest.csproj.DotSettings
new file mode 100644
index 00000000..6cbf8796
--- /dev/null
+++ b/test/TensorFlowNET.UnitTest/TensorFlowNET.UnitTest.csproj.DotSettings
@@ -0,0 +1,2 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=utilities/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>
\ No newline at end of file