Get KnwKB.

        Url parameters:
            - from: filter "mappings from"
            - to: filter "mappings to"
            - page
            - per_page
            - match_type: s=substring, e=exact, sw=startswith
            - sortby: 'from' or 'to'

def get(self, slug):
        """Get KnwKB.

        Url parameters:
            - from: filter "mappings from"
            - to: filter "mappings to"
            - page
            - per_page
            - match_type: s=substring, e=exact, sw=startswith
            - sortby: 'from' or 'to'
        """
        kb = api.get_kb_by_slug(slug)

        # check if is accessible from api
        check_knowledge_access(kb)

        parser = reqparse.RequestParser()
        parser.add_argument(
            'from', type=str,
            help="Return only entries where key matches this.")
        parser.add_argument(
            'to', type=str,
            help="Return only entries where value matches this.")
        parser.add_argument('page', type=int,
                            help="Require a specific page")
        parser.add_argument('per_page', type=int,
                            help="Set how much result per page")
        parser.add_argument('match_type', type=str,
                            help="s=substring, e=exact, sw=startswith")
        parser.add_argument('sortby', type=str,
                            help="the sorting criteria ('from' or 'to')")
        args = parser.parse_args()
        kb_dict = kb.to_dict()
        kb_dict['mappings'] = KnwKBMappingsResource \
            .search_mappings(kb=kb, key=args['from'], value=args['to'],
                             match_type=args['match_type'],
                             sortby=args['sortby'], page=args['page'],
                             per_page=args['per_page'])
        return kb_dict