File "/usr/lib/python3/dist-packages/IPython/config/__init__.py", line 16, in <module> from .application import * File "/usr/lib/python3/dist-packages/IPython/config/application.py", line 31, in <module> from IPython.config.configurable import SingletonConfigurable File "/usr/lib/python3/dist-packages/IPython/config/configurable.py", line 33, in <module> from IPython.utils.text import indent, wrap_paragraphs File "/usr/lib/python3/dist-packages/IPython/utils/text.py", line 28, in <module> from IPython.external.path import path File "/usr/lib/python3/dist-packages/IPython/external/path/__init__.py", line 2, in <module> from path import * File "/home/jhammel/python/path.py", line 25 print root(path) ^

#!/usr/bin/env python

# see also: http://www.daniweb.com/software-development/python/threads/66697

class Foo(object):
  def __init__(self, mutable=['default']):
    self.foo = mutable
    self.foo.append(1)

if __name__ == '__main__':
  bar = Foo()
  print len(bar.foo)
  fleem = Foo()
  print len(fleem.foo)
  assert len(fleem.foo) == 2, "Don't use default mutable arguments!"