keeping filter states after edits

def add_view(self, request, *args, **kwargs):
        result = super(LocationAdmin, self).add_view(request, *args, **kwargs )
        """
        Delete the session key, since we want the user to be directed to all listings
        after a save on a new object.
        """
        request.session['filtered'] =  None
        
        return result
    """
    Used to redirect users back to their filtered list of locations if there were any
    """    
    def change_view(self, request, object_id, extra_context={}):
        """
        save the referer of the page to return to the filtered
        change_list after saving the page
        """
        result = super(LocationAdmin, self).change_view(request, object_id, extra_context )
        
        # Look at the referer for a query string '^.*\?.*$'
        ref = request.META.get('HTTP_REFERER', '')
        if ref.find('?') != -1:
            # We've got a query string, set the session value
            request.session['filtered'] =  ref
        
        if request.POST.has_key('_save'):
            """
            We only kick into action if we've saved and if
            there is a session key of 'filtered', then we
            delete the key.
            """
            try:
                if request.session['filtered'] is not None:
                    result['Location'] = request.session['filtered']
                    request.session['filtered'] = None
            except:
                pass
                
        return result