## Create a `websocket` { #create-a-websocket }

In your **FastAPI** application, create a `websocket`:

{* ../../docs_src/websockets/tutorial001.py hl[1,46:47] *}

/// note | Technical Details

You could also use `from starlette.websockets import WebSocket`.

**FastAPI** provides the same `WebSocket` directly just as a convenience for you, the developer. But it comes directly from Starlette.

///

// error returned in IAM subsystem when user doesn't exist.
var errNoSuchUser = errors.New("Specified user does not exist")

// error returned by IAM when a use a builtin IDP command when they could mean
// to use a LDAP command.
var errNoSuchUserLDAPWarn = errors.New("Specified user does not exist. If you meant a user in LDAP please use command under `mc idp ldap`")

// error returned when service account is not found

//
//	func (c *wrapperConnPool) BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error) {
//		 return c.db.BeginTx(ctx, opts)
//	}
//
// You should use BeginTx returned gorm.Tx which could wrap *sql.Tx then you can record all queries.
func (c *wrapperConnPool) BeginTx(ctx context.Context, opts *sql.TxOptions) (gorm.ConnPool, error) {
	tx, err := c.db.BeginTx(ctx, opts)
	if err != nil {
		return nil, err
	}

            if (!createIndexResponse.isAcknowledged()) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Could not create next index: {}", indexName);
                }
                throw new SuggesterException("Could not create next index: " + indexName);
            }

    }
    
    @Override
    public void onRegistrationExpired(WitnessRegistration registration) {
        log.warn("Witness registration expired: {}", registration.getRegistrationId());
        // Could attempt re-registration here
    }
}

private void handleWitnessEvent(WitnessNotification notification) {
    log.info("Handling witness event: {} for resource: {}", 

  }

  @GwtIncompatible // different overflow behavior; could probably be made to work by using ~~
  public void testConcat_overflow_negative() {
    int dim1 = 1 << 16;
    int dim2 = 1 << 15;
    assertThat(dim1 * dim2).isLessThan(0);
    testConcatOverflow(dim1, dim2);
  }

  @GwtIncompatible // different overflow behavior; could probably be made to work by using ~~

                logger.info("Start scheduler \"{}\"", schedulerId);
                return;
            }
            ThreadUtil.sleep(1000L);
        }
        fail("could not start job.");
    }

    protected static void waitJob(final String namePrefix) {
        Boolean isRunning = false;
        int count = 0;

            }
            // parse a content
            parser.parse(is, handler);

            return handler.getDataMap();
        } catch (final Exception e) {
            throw new CrawlerSystemException("Could not create a data map from XML content.", e);
        }
    }

    private static class DocHandler extends DefaultHandler {
        private final Map<String, Object> dataMap = new HashMap<>();

        : new SparseImmutableTable<R, C, V>(cellList, rowSpace, columnSpace);
  }

  /**
   * @throws IllegalArgumentException if {@code existingValue} is not null.
   */
  /*
   * We could have declared this method 'static' but the additional compile-time checks achieved by
   * referencing the type variables seem worthwhile.
   */

<div class="screenshot">
<img src="/img/tutorial/separate-openapi-schemas/image02.png">
</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).