Prints all of the permutations of a given string

permutations.py

def permutations(str_value):
    chars = list(str_value)
    used_chars = [False] * len(str_value)
    return _permute(chars, used_chars, "")

def _permute(chars, used_chars, current):
    if len(current) == len(used_chars):
        yield current
    else:
        for i, used_char in enumerate(used_chars):
            if not used_chars[i]:
                used_chars[i] = True
                for permutation in permute(chars, used_chars, chars[i] + current):
                    yield permutation
                used_chars[i] = False

for p in permutations('gist'):
    print p