code: def apply(self, dir_or_plan=None, input=False, skip_plan=False, no_color=IsFlagged,
                **kwargs):
          
          default = kwargs
          default['input'] = input
          default['no_color'] = no_color
          default['auto-approve'] = (skip_plan == True)
          option_dict = self._generate_default_options(default)
          args = self._generate_default_args(dir_or_plan)
          return self.cmd('apply', *args, **option_dict)
docs: refer to https://terraform.io/docs/commands/apply.html
          no-color is flagged by default
          :param no_color: disable color of stdout
          :param input: disable prompt for a missing variable
          :param dir_or_plan: folder relative to working folder
          :param skip_plan: force apply without plan (default: false)
          :param kwargs: same as kwags in method 'cmd'
          :returns return_code, stdout, stderr