def posofend(str1, str2):
    """returns the position immediately _after_ the end of the occurence
    of str2 in str1.  If str2 is not in str1, return -1.
    """
    pos = str1.find(str2)
    if pos>-1:
        ret= pos+len(str2)
    else:
        ret = -1
    return ret