Rainbow Quirk

import math
#Rainbow
Rainbow = ('8B00FF','4B0082','00DDFF','00B200','D9D000','FF7F00','FF0000')
def gradientRainbow(text):
    leng = len(text)
    output = ''
    if leng < 7:
        for i in range(0, leng):
            output += '<c=#%s>' % Rainbow[i]
        for i in range(0, leng):
            output += text[i] + '</c>'
    else:
        output += '<c=#'
        output += '><c=#'.join(Rainbow)
        output += '>'
        size = int(math.ceil(leng / 7.0))
        for i in range(1, 8):
            output += text[(i-1)*size:i*size] + '</c>'
    return output
gradientRainbow.command="Rainbow"
#usage regex replace ^(.*)$ -> functionname(\1)