let insert_level entry e1 symbols action slev =
                  match e1 with
                  | true ->
                      {
                        assoc = slev.assoc;
                        lname = slev.lname;
                        lsuffix =
                          insert_tree entry symbols action slev.lsuffix;
                        lprefix = slev.lprefix;
                      }
                  | false ->
                      {
                        assoc = slev.assoc;
                        lname = slev.lname;
                        lsuffix = slev.lsuffix;
                        lprefix =
                          insert_tree entry symbols action slev.lprefix;
                      }