Swimbot Error

Traceback (most recent call last):
  File "/home/pi/.local/lib/python3.7/site-packages/discord/ext/commands/core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "/home/pi/Swimbot/whois.py", line 186, in refresh
    for tag in tags:
TypeError: 'NoneType' object is not iterable