code: @Override
      public Uri insert(Uri uri, ContentValues values) {
          Uri result = null;
  
          if (!controller.hasPreinitialized()) {
              throw new IllegalStateException("Controller has not been initialized.");
          }
  
          int patternCode = controller.getUriMatcher().match(uri);
          MatcherPattern pattern = controller.findMatcherPattern(patternCode);
          if (pattern == null) {
              throw new IllegalArgumentException("unknown uri : " + uri.toString());
          }
  
          Parameter parameter = new Parameter(uri, values);
          SQLiteDatabase db = this.getHelper().getWritableDatabase();
  
          result = onInsert(this.getHelper(), db, pattern, parameter);
          if (result != null) {
              this.onInsertCompleted(result, uri, pattern, parameter);
          }
          return result;
      }
docs: /*
  @see android.content.ContentProvider#insert(android.net.Uri, android.content.ContentValues)