your probably doing a comparison wrong. its >7 not =7

i solved the training module called "mumbling"
my answer is identical to the solution but its saying its wrong...
what do i need to do

import sys
def accum(s):
# your code
i = 0
j = 1
while i < len(s):
a = s[i] * j
sys.stdout.write(a.title())
sys.stdout.write("-")
i += 1
j += 1