def check_credentials(self):
try:<EOL><INDENT>return bool(self.mturk.get_account_balance())<EOL><DEDENT>except NoCredentialsError:<EOL><INDENT>raise MTurkServiceException("<STR_LIT>")<EOL><DEDENT>except ClientError:<EOL><INDENT>raise MTurkServiceException("<STR_LIT>")<EOL><DEDENT>except Exception as ex:<EOL><INDENT>raise MTurkServiceException(<EOL>"<STR_LIT>".format(str(ex))<EOL>)<EOL><DEDENT>
Verifies key/secret/host combination by making a balance inquiry