I found an interesting problem on https://www.codewars.com/kata/52dbae61ca039685460001ae:
Create a function which accepts one arbitrary string as an argument, and return a string of length 26.

The objective is to set each of the 26 characters of the output string to either `'1'` or `'0'` based on the fact whether the Nth letter of the alphabet is present in the input (independent of its case).

So if an `'a'` or an `'A'` appears anywhere in the input string (any number of times), set the first character of the output string to `'1'`, otherwise to `'0'`. if `'b'` or `'B'` appears in the string, set the second character to `'1'`, and so on for the rest of the alphabet.

For instance:

```
"a   **&  cZ"  =>  "10100000000000000000000001"
```

I tried it in Python, but could not do it. Can you solve it?
def change(stg):
    chars = set(stg.lower())
    return "".join(str(int(c in chars)) for c in "abcdefghijklmnopqrstuvwxyz")