Theano/Theano — pull request #1559 by jbornschein (2013-10-09 22:42:21+00:00)
Title: Use empty lists as default args where appropriate  (cosmetics)

Is there a reason why you chose to use arg=None as default value and then do "if arg is None: arg=[]"? \
I think the methods signature is more clear and the functions are slightly shorter when "arg=[]" is
directly used as default value.

If you think this is a reasonable change, I would look for more instances of this.