def fetch_command(self, subcommand):
        try:
            app_name = get_commands()[subcommand]
        except KeyError:
            sys.stderr.write("Unknown command: %r\nType '%s help' for usage.\n" % \
                             (subcommand, self.prog_name))
            sys.exit(1)
        if isinstance(app_name, BaseCommand):
            # If the command is already loaded, use it directly.
            klass = app_name
        else:
            klass = load_command_class(app_name, subcommand)
        return klass
the hausdorff distance between two sets is the maximum of the distances from a point in any of the sets to the nearest point in the other set
dataset/ETHPy150Open VikParuchuri/percept/percept/management/base.py/Management.fetch_command--crossover with--dataset/ETHPy150Open neuropoly/spinalcordtoolbox/scripts/sct_compute_hausdorff_distance.py/HausdorffDistance.__init__