how do i convince my parents to let me dye my hair?

hey guysss how do i convince my parents to let me dye my hair?? i’ve been thinking of just dyeing it black (my natural hair is brown) with maybe some colored streaks in it if i can, but my parents won’t say yes :// i’ve been asking for years but they won’t give in LMAOO how do i convince them? any advice is appreciated!! ^-^