Django: Where to put helper functions?

I usually put such app specific helper function in file utils.py and use someting like this

from myapp.utils import my_cool_func

def view_coolness(request):
    data = my_cool_func(request)
    return render_to_response("xxx.html")

but it depends what you helper does, may be they modify request , the could be part of middleware, so you need to tell what exactly those helper functions do