def check_issubset(to_check, original):
    """
    Check that contain of iterable ``to_check`` is among iterable ``original``.
    :param to_check:
        Iterable with elements to check.
    :param original:
        Iterable with elements to check to.
    :return:
        Boolean.
    """
    s = set()
    # Need this because ``set`` remove double letters like ``RR``
    for item in to_check:
        s.add(item)
    return s.issubset(original)