code: func GetInt(n ast.Node) (int64, error) {
  	if node, ok := n.(*ast.BasicLit); ok && node.Kind == token.INT {
  		return strconv.ParseInt(node.Value, 0, 64)
  	}
  	return 0, fmt.Errorf("Unexpected AST node type: %T", n)
  }
docs: // GetInt will read and return an integer value from an ast.BasicLit