code: def rez_bin_path(self):
          
          binpath = None
          if sys.argv and sys.argv[0]:
              executable = sys.argv[0]
              path = which("rezolve", env={"PATH":os.path.dirname(executable),
                                           "PATHEXT":os.environ.get("PATHEXT",
                                                                    "")})
              binpath = os.path.dirname(path) if path else None
  
          # TODO: improve this, could still pick up non-production 'rezolve'
          if not binpath:
              path = which("rezolve")
              if path:
                  binpath = os.path.dirname(path)
  
          if binpath:
              validation_file = os.path.join(binpath, ".rez_production_install")
              if os.path.exists(validation_file):
                  return os.path.realpath(binpath)
  
          return None
docs: Get path containing rez binaries, or None if no binaries are
          available, or Rez is not a production install.