[algorithm] Decode prototype content if python is older than 3.6

Fixes #71
2 jobs for 71_fix_algorithm_prototype_loading in 19 minutes and 58 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #160078
docker-build
build_linux_36

00:11:34

64.0%
passed #160079
macosx
build_macosx_36

00:19:58

64.0%