def _pipe_segment_with_colons(align, colwidth):
    """Return a segment of a horizontal line with optional colons which
    indicate column's alignment (as in `pipe` output format)."""
    w = colwidth
    if align in ["right", "decimal"]:
        return ('-' * (w - 1)) + ":"
    elif align == "center":
        return ":" + ('-' * (w - 2)) + ":"
    elif align == "left":
        return ":" + ('-' * (w - 1))
    else:
        return '-' * w