// Detect the first bar of a new month is_new_month = (month != month[1])
// Draw vertical lines on the first bar of a new month if is_new_month line.new(x1=bar_index, y1=high + 100, x2=bar_index, y2=low - 100, color=color.new(color.white, 80), width=1, extend=extend.none)