[data] Fix wrong instance variable name

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

00:02:56

73.0%
passed #191229
docker
build_linux_37

00:02:57

73.0%
passed #191226
macosx
build_macosx_36

00:02:43

73.0%
passed #191227
macosx
build_macosx_37

00:02:38

73.0%