code: function getParentheses() {
    const type = NodeType.ParenthesesType;
    const token = tokens[pos];
    const line = token.ln;
    const column = token.col;
    const right = token.right;
    let content = [];
  
    // Skip `(`.
    pos++;
  
    if (pos < right) {
      content = getTsets();
    }
  
    const end = getLastPosition(content, line, column, 1);
  
    // Skip `)`.
    pos++;
  
    return newNode(type, content, line, column, end);
  }
docs: Get node with text inside parentheses, e.g. `(1)`
  @return {Node}