in lib/MongoManager.ts [122:131]
async getCollection(serverName: string, databaseName: string, collectionName: string): Promise<Collection | undefined> {
const server = this.getServer(serverName);
if (server instanceof Error) { return; }
const database = await server.database(databaseName);
if (!database) { return; }
const collection = await database.collection(collectionName);
return collection;
}