Your task is to write an update for a lottery machine. Its current version produces a sequence of random letters and integers (passed as a string to the function). Your code must filter out all letters and return **unique** integers as a string, in their order of first appearance. If there are no integers in the string return `"One more run!"`
## Examples
```
"hPrBKWDH8yc6Lt5NQZWQ"  -->  "865"
"ynMAisVpHEqpqHBqTrwH"  -->  "One more run!"
"555"                   -->  "5"
```
def lottery(s):
    buffer = []
    for char in s:
        if char.isdigit() and char not in buffer:
            buffer.append(char)
    if buffer:
        return ''.join(buffer)
    else:
        return 'One more run!'
def lottery(s):
    buffer = []
    for char in s:
        if char.isdigit() and char not in buffer:
            buffer.append(char)
    if buffer:
        return ''.join(buffer)
    else:
        return 'One more run!'