Is the method correct? Because when I tried to use it on items, it returned false on every one. So I copied this method to my mod, and Intellij inspection showed that CommonInternals.objectTags might not contain strings in its keys. I changed CommonInternals.objectTags.get(stack.serializeNBT().toString() to CommonInternals.objectTags.get(stack.serializeNBT().toString().hashCode()) and it now works properly.

This won't be resolved ever