def remove_root_objective_bank(self, alias=None, objective_bank_id=None):
url_path = self._urls.roots(alias=alias)<EOL>current_root_ids = self._get_request(url_path)['<STR_LIT>']<EOL>modified_list = []<EOL>for root_id in current_root_ids:<EOL><INDENT>if root_id != str(objective_bank_id):<EOL><INDENT>modified_list.append(root_id)<EOL><DEDENT><DEDENT>new_root_ids = {<EOL>'<STR_LIT>': modified_list<EOL>}<EOL>return self._put_request(url_path, new_root_ids)<EOL>
Removes a root objective bank.

        arg:    objective_bank_id (osid.id.Id): the ``Id`` of an
                objective bank
        raise:  NotFound - ``objective_bank_id`` is not a root
        raise:  NullArgument - ``objective_bank_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*