def add_user(self, group, username):
        """
        Add a user to the specified LDAP group.

        Args:
            group: Name of group to update
            username: Username of user to add

        Raises:
            ldap_tools.exceptions.InvalidResult:
                Results of the query were invalid.  The actual exception raised
                inherits from InvalidResult.  See #lookup_id for more info.

        """
        try:
            self.lookup_id(group)
        except ldap_tools.exceptions.InvalidResult as err:  # pragma: no cover
            raise err from None

        operation = {'memberUid': [(ldap3.MODIFY_ADD, [username])]}
        self.client.modify(self.__distinguished_name(group), operation)
Add a user to the specified LDAP group.

        Args:
            group: Name of group to update
            username: Username of user to add

        Raises:
            ldap_tools.exceptions.InvalidResult:
                Results of the query were invalid.  The actual exception raised
                inherits from InvalidResult.  See #lookup_id for more info.