pre := fmt.Sprintf("%s(%q): ", statname, devNullName)
	if fi.Size() != 0 {
		t.Errorf(pre+"wrong file size have %d want 0", fi.Size())
	}
	if fi.Mode()&ModeDevice == 0 {
		t.Errorf(pre+"wrong file mode %q: ModeDevice is not set", fi.Mode())
	}
	if fi.Mode()&ModeCharDevice == 0 {
		t.Errorf(pre+"wrong file mode %q: ModeCharDevice is not set", fi.Mode())
	}
	if fi.Mode().IsRegular() {

    tf_device.return %identity : tensor<i32>
  }) {device = "some_device"} : () -> (tensor<i32>)
  return %launch : tensor<i32>
}
```

will be transformed into:

```mlir
func @computation(%arg0: tensor<i32>) -> tensor<i32> {
  %launch = "tf_device.launch_func"(%arg0) {device = "some_device", func = @_func} : (tensor<i32>) -> tensor<i32>
  return %launch : tensor<i32>
}