Fix pyflakes invocation in nix.
Created by: tomprince
It turns our that pyflakes with no arguments expects input
on stdin. In CI, this is likely connected to /dev/null so it
passes.
Also fix the errors that pyflakes is reporting.
Created by: tomprince
It turns our that pyflakes with no arguments expects input
on stdin. In CI, this is likely connected to /dev/null so it
passes.
Also fix the errors that pyflakes is reporting.