SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function mapFilter (children 1)
     ExpressionList (children 1)
      Function lambda (children 1)
       ExpressionList (children 2)
        Function tuple (children 1)
         ExpressionList (children 2)
          Identifier x
          Identifier y
        Function tuple (children 1)
         ExpressionList (children 2)
          Identifier x
          Function plus (children 1)
           ExpressionList (children 2)
            Identifier x
            Literal UInt64_1