code: def get_units_from_category(self, category) -> typing.Iterator['BaseUnit']:
          
          Mission.validator_group_category.validate(category, 'group category')
          for unit in self.units:
  
              if unit.group_category == category:
                  yield unit
docs: Args:
              category: unit category
  
          Returns: generator over all units of a specific category in this coalition