camel case to snake case

camel_to_snake.py

def camel_to_snake(name):
    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
    return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()

# convert comma separated csv header
keys = header.split(',')
keys = [camel_to_snake(k) for k in keys]
header = ','.join(keys)