updated xml_size;

--- a/src/HOL/Proofs/ex/XML_Data.thy	Mon Nov 04 15:06:54 2019 +0100
+++ b/src/HOL/Proofs/ex/XML_Data.thy	Mon Nov 04 15:14:34 2019 +0100
@@ -51,7 +51,9 @@
 ML_val \<open>
   val xml = export_proof thy1 @{thm abs_less_iff};
   val thm = import_proof thy1 xml;
-  \<^assert> (size (YXML.string_of_body xml) > 500000);
+
+  val xml_size = size (YXML.string_of_body xml);
+  \<^assert> (xml_size > 400000);
 \<close>
 
 end