Search for a character in an iterable and return an index of all occurrences of that character.

Recursive Find

def recursvfind (search, target, start=0, pos=[]):
    current_pos = str(target).find(search, start)
    
    if current_pos < 0:
        return pos
    else:
        return recursvfind(search, target, current_pos + 1, pos + [current_pos])