Yields all subsequences of input string

get_subsequences.py

#!/usr/bin/python

from itertools import combinations

def get_subsequences(input_str):
    '''
    Yields all subsequences of size in range [1, len(input_str)]
    '''
    if type(input_str) == str:
        for length in range(1, len(input_str)+1):
            for elems in combinations(input_str, length):
                yield ','.join(elems)
    else:
        raise GeneratorExit

if __name__ == '__main__':
        for output in get_subsequences('hello'):
            print output