Help moding python script to edit Gcode

[AntaresSky]

import sys
import os

if len(sys.argv) != 2:
    print('Usage: python nocomment.py <file.gcode>')
    sys.exit(1)
    
in_file = os.path.abspath(sys.argv[1])

if not os.path.isfile(in_file):
    print(in_file + ' does not exist!')
    sys.exit(1)

with open(in_file, 'r+') as f:
    out_lines = []
    for line in f.readlines():
       if line.lstrip().startswith(';'):
        out.lines.append("(" + line + ")")
       else:
        out_lines.append(line)
            
    if(len(out_lines) > 0):
        f.seek(0)
        f.truncate()
        f.writelines(out_lines)
        
print('comment line complete for ' + in_file)