public static @Nullable ASTNode getPreviousNonWhitespaceLeaf(@Nullable ASTNode node) {
    if (node == null) return null;
    ASTNode treePrev = node.getTreePrev();
    if (treePrev != null) {
      ASTNode candidate = TreeUtil.getLastChild(treePrev);
      if (candidate != null && !isWhitespaceOrEmpty(candidate)) {
        return candidate;
      }
      else {
        return getPreviousNonWhitespaceLeaf(candidate);
      }
    }
    final ASTNode treeParent = node.getTreeParent();

    if (treeParent == null || treeParent.getTreeParent() == null) {
      return null;
    }
    else {
      return getPreviousNonWhitespaceLeaf(treeParent);
    }
  }
public static @Nullable ASTNode getPreviousNonWhitespaceLeaf(@Nullable ASTNode node)