<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def revision_list( request, template_name='wakawaka/revision_list.html', extra_context=None ):
 """ Displays a list of all recent revisions. """

    revision_list = Revision.objects.all()
    template_context = {'revision_list': revision_list}
    template_context.update(extra_context or {})
    return render(request, template_name, template_context)