code: def subparsers(self):
          
          if self._subparsers is None:
              apkw = {
                  'title': 'commands',
                  'description': 'Commands for the %s program' % self.parser.prog,
              }
              self._subparsers = self.parser.add_subparsers(**apkw)
          return self._subparsers
docs: Insantiates the subparsers for all commands