python - I need this Substring counting program to return a Tuple -

i have come piece of code count multiple substrings within string. need return results in tuple. suggestions?

def findsubstringmatch(target, key):     positionlist = 0     while positionlist < len(target):         positionlist = target.find(key, positionlist)         if positionlist == -1:             break         print(positionlist)         positionlist += 2  findsubstringmatch("atgacatgcacaagtatgcat", "atgc") 

this piece of code prints: 5 15

i return: (5,15)

try this:

def findsubstringmatch(target, key):     positionlist = 0     result = []     while positionlist < len(target):         positionlist = target.find(key, positionlist)         if positionlist == -1:             break         result.append(positionlist)         positionlist += 2     return tuple(result) 

even better, can simplify whole function this:

from re import finditer  def findsubstringmatch(target, key):     return tuple(m.start() m in finditer(key, target)) 

either way, works expected:

findsubstringmatch("atgacatgcacaagtatgcat", "atgc") => (5, 15)