simple Mongodb database factory implementation

MongoDatabaseFactory.cs

public class MongoDatabaseFactory : IMongoDatabaseFactory
{
  public IMongoDatabase Connect(string connectionString, string dbName)
  {
    if(string.IsNullOrWhiteSpace(connectionString))
        throw new ArgumentNullException("connectionString");
    if (string.IsNullOrWhiteSpace(dbName))
        throw new ArgumentNullException("dbName");

    var dbClient = new MongoClient(connectionString);
    return dbClient.GetDatabase(dbName);
  }
}