This one is particularly confusing as this works:

source_root_stripped_sources = await MultiGet(
    Get(SourceRootStrippedSources, HydratedTarget, target_adaptor)
    for target_adaptor in all_targets
  )

But this:

source_root_stripped_source = await Get(SourceRootStrippedSources, HydratedTarget, test_target)

results in the above error when added to the same file.