bot error

Jul 04 13:41:49 openstudyroom.org python[10919]: UnboundLocalError: local variable 'servers' referenced before assignment
Jul 04 13:41:49 openstudyroom.org python[10919]: The above exception was the direct cause of the following exception:
Jul 04 13:41:49 openstudyroom.org python[10919]: Traceback (most recent call last):
Jul 04 13:41:49 openstudyroom.org python[10919]:   File "/home/climu/osr_bot/venv/lib/python3.5/site-packages/discord/ext/commands/bot.py", line 8
Jul 04 13:41:49 openstudyroom.org python[10919]:     yield from ctx.command.invoke(ctx)
Jul 04 13:41:49 openstudyroom.org python[10919]:   File "/home/climu/osr_bot/venv/lib/python3.5/site-packages/discord/ext/commands/core.py", line 
Jul 04 13:41:49 openstudyroom.org python[10919]:     yield from injected(*ctx.args, **ctx.kwargs)
Jul 04 13:41:49 openstudyroom.org python[10919]:   File "/home/climu/osr_bot/venv/lib/python3.5/site-packages/discord/ext/commands/core.py", line 
Jul 04 13:41:49 openstudyroom.org python[10919]:     raise CommandInvokeError(e) from e
Jul 04 13:41:49 openstudyroom.org python[10919]: discord.ext.commands.errors.CommandInvokeError: Command raised an exception: UnboundLocalError: l
Jul 04 13:41:49 openstudyroom.org python[10919]: Ignoring exception in command whos:
Jul 04 13:41:49 openstudyroom.org python[10919]: Traceback (most recent call last):
Jul 04 13:41:49 openstudyroom.org python[10919]:   File "/home/climu/osr_bot/venv/lib/python3.5/site-packages/discord/ext/commands/core.py", line 
Jul 04 13:41:49 openstudyroom.org python[10919]:     ret = yield from coro(*args, **kwargs)
Jul 04 13:41:49 openstudyroom.org python[10919]:   File "/home/climu/osr_bot/OSR-discord-bot/bot.py", line 184, in whos
Jul 04 13:41:49 openstudyroom.org python[10919]:     message += user_info_message(user, infos)
Jul 04 13:41:49 openstudyroom.org python[10919]:   File "/home/climu/osr_bot/OSR-discord-bot/utils.py", line 34, in user_info_message
Jul 04 13:41:49 openstudyroom.org python[10919]:     message += ' - '.join(servers) + '\n'