code: def _validate(self):
          
          if self.region_type not in regions_attributes:
              raise ValueError("'{0}' is not a valid region type in this package"
                               .format(self.region_type))
  
          if self.coordsys not in valid_coordsys['DS9'] + valid_coordsys['CRTF']:
              raise ValueError("'{0}' is not a valid coordinate reference frame "
                               "in astropy".format(self.coordsys))
docs: Checks whether all the attributes of this object is valid.