Hi!

The code print(''.format(x)) (missing the brackets reference) raises an error in vim (E155: Unknown sign: Pymode').

The traceback refers to Error detected while processing function pymode#lint#check from the pymode plugin.

It seems to be a case not handled in the function PymodeSigns.place(loclist) (file autoload/pymode/tools/signs.vim) where the issue.type[0] is a quote (') and does not refer to any defined sign.

I am not sure about this quick traceback investigation, but I feel like it could be handled as a "warning" or "error" by the pymode plugin instead of raising a vim error.

Thanks and best regards!