def get_assessment_session_for_bank(self, bank_id=None, proxy=None):
if bank_id is None or proxy is None:<EOL><INDENT>raise NullArgument<EOL><DEDENT>raise Unimplemented()<EOL>
Gets an ``AssessmentSession`` which is responsible for performing assessments for the given bank ``Id``.

        arg:    bank_id (osid.id.Id): the ``Id`` of a bank
        arg:    proxy (osid.proxy.Proxy): a proxy
        return: (osid.assessment.AssessmentSession) - an assessment
                session for this service
        raise:  NotFound - ``bank_id`` not found
        raise:  NullArgument - ``bank_id`` or ``proxy`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_assessment()`` is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_assessment()`` is ``true``.*