def findIndexes(text, subString):
    """
        Returns a set of all indexes of subString in text.
    """
    indexes = set()
    lastFoundIndex = 0
    while True:
        foundIndex = text.find(subString, lastFoundIndex)
        if foundIndex == -1:
            break
        indexes.add(foundIndex)
        lastFoundIndex = foundIndex + 1
    return indexes