在R中的图的图例中，你如何去除一个奇怪的错误的颜色边框？

# 创建图例对象
my_legend <- legend(x = "topright", legend = c("Group 1", "Group 2"), col = c("red", "blue"))

# 查看图例对象的结构
str(my_legend)

# 修改图例对象的属性
my_legend$rect$col <- "transparent"
my_legend$rect$border <- NA

# 重新绘制图例
legend(x = my_legend$x, y = my_legend$y, legend = my_legend$legend, col = my_legend$col, pch = my_legend$pch, lty = my_legend$lty, lwd = my_legend$lwd, bg = my_legend$bg, text.col = my_legend$text.col, cex = my_legend$cex, pt.cex = my_legend$pt.cex, pt.bg = my_legend$pt.bg, bty = my_legend$bty, inset = my_legend$inset)