@Nullable
  default <T extends PyAstElement> T childToPsi(@NotNull TokenSet elTypes) {
    final ASTNode node = getNode().findChildByType(elTypes);
    //noinspection unchecked
    return node != null ? (T)node.getPsi() : null;
  }
@Nullable
  default <T extends PyAstElement> T childToPsi(@NotNull TokenSet elTypes)