Remove redundant __nonzero__ methods
From https://docs.python.org/2/reference/datamodel.html#specialnames :
When this method is not defined, __len__() is called, if it is
defined, and the object is considered true if its result is nonzero.
Also helpful for an eventual migration to py3k, as __nonzero__ has been
replaced with __bool__, which also defaults to looking at __len__ if
undefined.
# -*- coding: utf-8 -*-
###############################################################################
#
# Put here information about external resources / styles used by your cube,
# or to overides existing UI properties.
#
# Existing properties are available through the `sheet` dictionary available
# in the global namespace. You also have access to a `data` function which
# will return proper url for resources in the 'data' directory.
#
# /!\ this file should not be imported /!\
###############################################################################
# CSS stylesheets to include in HTML headers
# uncomment the line below to use template specific stylesheet
# STYLESHEETS = sheet['STYLESHEETS'] + [data('cubes.%(cubename)s.css')]