SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function hex (children 1)
     ExpressionList (children 1)
      Function approx_top_kState (children 2)
       ExpressionList (children 1)
        Literal Array_[\'str\']
       ExpressionList (children 1)
        Literal UInt64_3
