def find_all_overlapping(string, occurrence):
    """Find all overlapping occurrences.
    
    :param string: String to be searched.
    :type string: string
    
    :param occurrence: Occurrence to search.
    :type occurrence: string
    
    :return: generator yielding *positions of occurence*
    :rtype: generator of int
    
    """
    found = 0
    while True:
        found = string.find(occurrence, found)
        if found != -1:
            yield found
        else:
            return
        found += 1
