python split html header
from itertools import count
chapter_number = count(1)
output_file = open('000-intro.html', 'wb')
with open('index.html', 'rt') as input_file:
for line in input_file:
if '<h1' in line:
output_file.close()
output_file = open('{:03}-chapter'.format(next(chapter_number)), 'wb')
output_file.write(line)
output_file.close()