<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_regions(self):
 """Get the requested regions."""

        if self._specs_in[_REGIONS_STR] == 'all':
            return [_get_all_objs_of_type(
                Region, getattr(self._obj_lib, 'regions', self._obj_lib)
            )]
        else:
            return [set(self._specs_in[_REGIONS_STR])]