code: function hasOctalEscapeSequence(node) {
      if (isConcatenation(node)) {
          return hasOctalEscapeSequence(node.left) || hasOctalEscapeSequence(node.right);
      }
  
      return isOctalEscapeSequence(node);
  }
docs: Checks whether or not a node contains a octal escape sequence
  @param {ASTNode} node A node to check
  @returns {boolean} `true` if the node contains an octal escape sequence