miracle2k/webassets — pull request #327 by mankyd (2014-06-18 15:32:27+00:00)
Title: Don't use mutables as default arguments.

Using mutables as default arguments in Python can lead to terrible things. Specifically, if a list is used as a default, and its value is at all changed, the change carries forward to future invocations of the function. More can be read here: http://docs.python-guide.org/en/latest/writing/gotchas/