diff -up xgridfit/lib/xgridfit-python.xsl.py3 xgridfit/lib/xgridfit-python.xsl
--- xgridfit/lib/xgridfit-python.xsl.py3	2017-11-03 20:19:21.947851599 +0100
+++ xgridfit/lib/xgridfit-python.xsl	2017-11-03 20:19:46.137844915 +0100
@@ -540,11 +540,11 @@ CURRENT_FONT.maxp_maxStackDepth = 0
     try:
         CURRENT_FONT[name].ttinstrs = fontforge.parseTTInstrs(instrs)
     except TypeError as detail:
-        print "Warning: can't install instructions for glyph ", name
-        print detail
+        print ("Warning: can't install instructions for glyph ", name)
+        print (detail)
     except ValueError as detail:
-        print "Warning: can't install instructions for glyph ", name
-        print detail
+        print ("Warning: can't install instructions for glyph ", name)
+        print (detail)
 </xsl:text>
     <xsl:if test="$compile_globals='yes'">
       <xsl:text>CURRENT_FONT.cvt = (</xsl:text>