[data] Fix wrong instance variable name

4 jobs for fix_error_message in 2 minutes and 58 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_36 #191228
docker

00:02:56

73.0%
passed build_linux_37 #191229
docker

00:02:57

73.0%
passed build_macosx_36 #191226
macosx

00:02:43

73.0%
passed build_macosx_37 #191227
macosx

00:02:38

73.0%