SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier res
    Function map (alias res) (children 1)
     ExpressionList (children 4)
      Literal \'a\'
      Literal UInt64_1
      Literal \'b\'
      Literal \'str_1\'
