def classImplements(c, ms):
    """
    c is a class, and ms is a set of method names.  
    Returns True if c implements all the methods in c.  
    Complains otherwise, and returns False
    """
    result = True
    for n in ms:
        m = getattr(c, n, False)
        if not (m and callable(m)):
            print(c, "does not have method", n)
            result = False
    return result