def stringIsAmong(s, l):
    """Is p_s among list of strings p_l ? p_s can be a string or a
       list/tuple of strings. In this latter case, r_ is True if at least
       one string among p_s is among p_l."""
    if isinstance(s, str):
        return s in l
    for elem in s:
        if elem in l:
            return True
