argparser, make it possible to generate non-confusable passwords

pw.py

@@ -2,21 +2,25 @@
 
 import random
 
-def generate_pw(length):
+def generate_pw(length, no_confuse):
     import string
     charset = string.ascii_letters + string.digits + '+-_?!.:,;'
+    if no_confuse:
+        for c in '1Il0O':
+            charset = charset.replace(c, '')
     return ''.join([random.choice(charset) for _ in range(length)])
 
 def main():
-    import sys
     import os
-    import time
-    
-    if len(sys.argv) > 1:
-        length = int(sys.argv[1])
-    else:
-        length = 12
-    pw = generate_pw(length)
+    import argparse
+
+    parser = argparse.ArgumentParser(prog='Password Generator', description='Generate a random password')
+    parser.add_argument('-n', '--no-confuse', action='store_true', help='do not use easily confusable characters (1Il0O)')
+    parser.add_argument('length', nargs='?', type=int, default=20, help='length of the password')
+
+    args = parser.parse_args()
+
+    pw = generate_pw(args.length, args.no_confuse)
     print(pw)
 
     if os.name == 'nt':