def _must_split_flat_key_val(must):
    """
    Splits the flat and key:val tags apart

    :returns: the flat set tags and the key:val tags
    :rtype: tuple(set, dict)
    """
    key_val = {}
    flat = set()
    for i in must:
        if ':' in i:
            k, v = i.split(':', 1)
            key_val[k] = v
        else:
            flat.add(i)
    return flat, key_val
