code: function executeAuthRemoveUserCommand(db, username, options, callback) {
    if (typeof options === 'function') (callback = options), (options = {});
    options = options || {};
  
    // Did the user destroy the topology
    if (db.serverConfig && db.serverConfig.isDestroyed())
      return callback(new MongoError('topology was destroyed'));
    // Get the error options
    const commandOptions = { writeCommand: true };
    if (options['dbName']) commandOptions.dbName = options['dbName'];
  
    // Get additional values
    const maxTimeMS = typeof options.maxTimeMS === 'number' ? options.maxTimeMS : null;
  
    // Add maxTimeMS to options if set
    if (maxTimeMS != null) commandOptions.maxTimeMS = maxTimeMS;
  
    // Build the command to execute
    let command = {
      dropUser: username
    };
  
    // Apply write concern to command
    command = applyWriteConcern(command, { db }, options);
  
    // Force write using primary
    commandOptions.readPreference = ReadPreference.primary;
  
    // Execute the command
    executeCommand(db, command, commandOptions, (err, result) => {
      if (err && !err.ok && err.code === undefined) return handleCallback(callback, { code: -5000 });
      if (err) return handleCallback(callback, err, null);
      handleCallback(callback, null, result.ok ? true : false);
    });
  }
docs: Run the dropUser command.
  
  @param {Db} db The Db instance on which to execute the command.
  @param {string} username The username of the user to remove.
  @param {object} [options] Optional settings. See Db.prototype.removeUser for a list of options.
  @param {Db~resultCallback} [callback] The command result callback