It was given a historical lock, which means that it no longer appears in certain lists.
When you search for "python", your search is automatically redirected to the list of questions tagged python because it is one of Stack Overflow's top 40 tags. Questions with historical locks apparently don't appear there anymore, but they are supposed to appear in searches.
You can work around this by searching for questions both tagged as and containing "python". The quotation marks stop the system from converting it to a tag search.