A bit of cleanup. Also make all imports explicit or qualified

4 jobs for 399-o2-graphs-are-sometimes-generated-without-edges in 47 minutes and 39 seconds (queued for 9 minutes and 8 seconds)
latest
Status Job ID Name Coverage
  Cabal
passed #17799
cabal

00:19:59

 
  Stack
passed #17800
stack

00:03:01

 
  Bench
manual #17801
allowed to fail manual
bench
 
  Test
passed #17802
test

00:24:37