How to check if a 'Storage ' entry exists?

When I check for files without an added chunk number (f.i. file ABC.txt) it is recognised perfectly with your code, output is:

[
"news.txt\1",
"weath0.txt\1",
"weath1.txt\1",
"stocks.txt\1",
"messages.txt\1",
"ABC.txt"
]
exists

As @fanoush explained there are 2 methods to store a file, I happened to use the files with the added chunk number.