code: def _get_optional_attrs(kws):
          
          vals = OboOptionalAttrs.attributes.intersection(kws.keys())
          if 'sections' in kws:
              vals.add('relationship')
          if 'norel' in kws:
              vals.discard('relationship')
          return vals
docs: Given keyword args, return optional_attributes to be loaded into the GODag.