this derivation will be built:
  /nix/store/a2yr0bai5fbyjslrs409mjgpxb1jkc60-interpolate-conformance.drv
bld3: building a2yr0bai5fbyjslrs409mjgpxb1jkc60-interpolate-conformance.drv
10 cases: Nix interpolate == Python interpolate == expected