How to use the @vendure/core.Logger.error function in @vendure/core

Logger.debug(JSON.stringify(item.index.error, null, 2), loggerCtx);
                    }
                    if (item.update) {
                        Logger.debug(JSON.stringify(item.update.error, null, 2), loggerCtx);
                    }
                    if (item.delete) {
                        Logger.debug(JSON.stringify(item.delete.error, null, 2), loggerCtx);
                    }
                });
            } else {
                Logger.verbose(`Executed ${body.items.length} bulk operations on index [${fullIndexName}]`);
            }
            return body;
        } catch (e) {
            Logger.error(`Error when attempting to run bulk operations [${e.toString()}]`, loggerCtx);
            Logger.error('Error details: ' + JSON.stringify(e.body.error, null, 2), loggerCtx);
        }
    }

async onVendureBootstrap(): Promise {
        const { host, port } = ElasticsearchPlugin.options;
        try {
            const pingResult = await this.elasticsearchService.checkConnection();
        } catch (e) {
            Logger.error(`Could not connect to Elasticsearch instance at "${host}:${port}"`, loggerCtx);
            Logger.error(JSON.stringify(e), loggerCtx);
            return;
        }
        Logger.info(`Sucessfully connected to Elasticsearch instance at "${host}:${port}"`, loggerCtx);

        await this.elasticsearchService.createIndicesIfNotExists();

        this.eventBus.ofType(CatalogModificationEvent).subscribe(event => {
            if (event.entity instanceof Product || event.entity instanceof ProductVariant) {
                return this.elasticsearchIndexService.updateProductOrVariant(event.ctx, event.entity).start();
            }
        });

        const collectionModification$ = this.eventBus.ofType(CollectionModificationEvent);
        const closingNotifier$ = collectionModification$.pipe(debounceTime(50));
        collectionModification$
            .pipe(

}
            const result = await handler.handle(event as any, EmailPlugin.options.globalTemplateVars);
            if (!result) {
                return;
            }
            const bodySource = await this.templateLoader.loadTemplate(type, result.templateFile);
            const generated = await this.generator.generate(
                result.from,
                result.subject,
                bodySource,
                result.templateVars,
            );
            const emailDetails = { ...generated, recipient: result.recipient };
            await this.emailSender.send(emailDetails, this.transport);
        } catch (e) {
            Logger.error(e.message, 'EmailPlugin', e.stack);
        }
    }
}

private async deleteIndices(prefix: string) {
        try {
            const index = prefix + VARIANT_INDEX_NAME;
            await this.client.indices.delete({ index });
            Logger.verbose(`Deleted index "${index}"`, loggerCtx);
        } catch (e) {
            Logger.error(e, loggerCtx);
        }
        try {
            const index = prefix + PRODUCT_INDEX_NAME;
            await this.client.indices.delete({ index });
            Logger.verbose(`Deleted index "${index}"`, loggerCtx);
        } catch (e) {
            Logger.error(e, loggerCtx);
        }
    }

if (item.index) {
                        Logger.debug(JSON.stringify(item.index.error, null, 2), loggerCtx);
                    }
                    if (item.update) {
                        Logger.debug(JSON.stringify(item.update.error, null, 2), loggerCtx);
                    }
                    if (item.delete) {
                        Logger.debug(JSON.stringify(item.delete.error, null, 2), loggerCtx);
                    }
                });
            } else {
                Logger.verbose(`Executed ${body.items.length} bulk operations on index [${fullIndexName}]`);
            }
            return body;
        } catch (e) {
            Logger.error(`Error when attempting to run bulk operations [${e.toString()}]`, loggerCtx);
            Logger.error('Error details: ' + JSON.stringify(e.body.error, null, 2), loggerCtx);
        }
    }

private async createIndices(prefix: string) {
        try {
            const index = prefix + VARIANT_INDEX_NAME;
            await this.client.indices.create({ index });
            Logger.verbose(`Created index "${index}"`, loggerCtx);
        } catch (e) {
            Logger.error(JSON.stringify(e, null, 2), loggerCtx);
        }
        try {
            const index = prefix + PRODUCT_INDEX_NAME;
            await this.client.indices.create({ index });
            Logger.verbose(`Created index "${index}"`, loggerCtx);
        } catch (e) {
            Logger.error(JSON.stringify(e, null, 2), loggerCtx);
        }
    }

error: err => {
                        Logger.error(err);
                        reporter.complete(false);
                    },
                });