make it somewhat portable

pw.py

@@ -4,20 +4,23 @@ import random
 
 def generate_pw(length):
     import string
-    charset = string.ascii_letters + string.digits + '+-_?!.:,;';
+    charset = string.ascii_letters + string.digits + '+-_?!.:,;'
     return ''.join([random.choice(charset) for _ in range(length)])
 
 def main():
     import sys
     import os
     import time
-    import win32clipboard
+    
     if len(sys.argv) > 1:
         length = int(sys.argv[1])
     else:
         length = 12
     pw = generate_pw(length)
     print(pw)
+
+    if os.name == 'nt':
+        import win32clipboard
         win32clipboard.OpenClipboard()
         win32clipboard.EmptyClipboard()
         win32clipboard.SetClipboardText(pw, win32clipboard.CF_UNICODETEXT)