Args:
            category: group category

        Returns: generator over all groups from a specific category in this coalition

def get_groups_from_category(self, category) -> typing.Iterator['Group']:
        """
        Args:
            category: group category

        Returns: generator over all groups from a specific category in this coalition
        """
        Mission.validator_group_category.validate(category, 'get_groups_from_category')
        for group in self.groups:

            if group.group_category == category:
                yield group