'Returns the discussion tab for the given course.  It can be either of type \'discussion\'
or \'external_discussion\'.  The returned tab object is self-aware of the \'link\' that it corresponds to.'

@staticmethod
def get_discussion(course):

    if course.discussion_link:
        return CourseTab.load('external_discussion', name=_('External    Discussion'), link=course.discussion_link)
    for tab in course.tabs:
        if ((tab.type == 'discussion') or (tab.type == 'external_discussion')):
            return tab
    return None
