code: def requireExecutables(executables):
      
      missingExecutables = []
      for executable in executables:
          if getPathOfExecutable(executable) is None:
              missingExecutables.append(executable)
      if len(missingExecutables) > 0:
          log("In order to run this script, the following "
              "executables need to be on the path:")
          for missingExecutable in missingExecutables:
              log(missingExecutable)
          exit(1)
docs: Check that all of the given executables are on the path.
      If at least one of them is not, exit the script and inform
      the user of the missing requirement(s).