def result_headers(cl):
    """
    Generates the list column headers.
    """
    ordering_field_columns = cl.get_ordering_field_columns()
    for i, field_name in enumerate(cl.list_display):
        text, attr = label_for_field(field_name, cl.model,
            model_admin = cl.model_admin,
            return_attr = True
        )
        if attr:
            # Potentially not sortable

            # if the field is the action checkbox: no sorting and special class
            if field_name == 'action_checkbox':
                yield {
                    "text": text,
                    "class_attrib": mark_safe(' class="action-checkbox-column"'),
                    "sortable": False,
                }
                continue

            admin_order_field = getattr(attr, "admin_order_field", None)
            if not admin_order_field:
                # Not sortable
                yield {
                    "text": text,
                    "sortable": False,
                }
                continue

        # OK, it is sortable if we got this far
        th_classes = ['sortable']
        order_type = ''
        new_order_type = 'asc'
        sort_priority = 0
        sorted = False
        # Is it currently being sorted on?
        if i in ordering_field_columns:
            sorted = True
            order_type = ordering_field_columns.get(i).lower()
            sort_priority = list(ordering_field_columns).index(i) + 1
            th_classes.append(order_type % 'sorted %sending')
            new_order_type = {'asc': 'desc', 'desc': 'asc'}[order_type]

        # build new ordering param
        o_list_primary = [] # URL for making this field the primary sort
        o_list_remove  = [] # URL for removing this field from sort
        o_list_toggle  = [] # URL for toggling order type for this field
        make_qs_param = lambda t, n: ('-' if t == 'desc' else '') + str(n)

        for j, ot in ordering_field_columns.items():
            if j == i: # Same column
                param = make_qs_param(new_order_type, j)
                # We want clicking on this header to bring the ordering to the
                # front
                o_list_primary.insert(0, param)
                o_list_toggle.append(param)
                # o_list_remove - omit
            else:
                param = make_qs_param(ot, j)
                o_list_primary.append(param)
                o_list_toggle.append(param)
                o_list_remove.append(param)

        if i not in ordering_field_columns:
            o_list_primary.insert(0, make_qs_param(new_order_type, i))


        yield {
            "text": text,
            "sortable": True,
            "sorted": sorted,
            "ascending": order_type == "asc",
            "sort_priority": sort_priority,
            "url_primary": cl.get_query_string({ORDER_VAR: '.'.join(o_list_primary)}),
            "url_remove": cl.get_query_string({ORDER_VAR: '.'.join(o_list_remove)}),
            "url_toggle": cl.get_query_string({ORDER_VAR: '.'.join(o_list_toggle)}),
            "class_attrib": format_html(' class="{0}"', ' '.join(th_classes))
                            if th_classes else '',
        }
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/contrib/admin/templatetags/admin_list.py/result_headers/swapped operands of `%`