Starting up the pycodestyle syntax checker takes about one second, which is too much to launch it on each parse job. We should instead have some "server" script running, which processes data from stdin and writes checker errors to stdout. Example code on how to interface with pycodestyle:

>>> import pycodestyle
>>> c = pycodestyle.Checker(lines=["a=3"])
>>> c.check_all()
stdin:1:2: E225 missing whitespace around operator
stdin:1:4: W292 no newline at end of file
2