Shivank, there is currently technically no "error to solve", since we have no test that causes this erroneous behavior and catches it. We've only found what appears to be a bug by looking at the code, but we need to *verify* that it is indeed a bug. Also, this means that we have a piece of code that our test suite is missing; this is the real reason I insist that this needs a test.

You should trace what uses the affected code and which scenarios could lead to this bug causing unexpected behavior.

In this case, the code is in `_clone_node()`, which helpfully has the following comment in its doc-string: "Called by Node.cloneNode and Document.importNode". Work up from there, understand what this could affect, and think of a scenario where this code wouldn't work as expected.