SpecificRepositoryImpl.cs

public class PeriodRepository : IPeriodRepository
{
	// at this point, I have already created my DbContext which I will
	// then use to generate the database by running EF Code First commands
	private PeriodContext context;

	public PeriodRepository(PeriodContext context)
	{
		this.context = context;
	}

	public async Task AddAsync(Period domainObject)
	{
		this.context.Set<Period>().Add(domainObject);
		await this.context.SaveChangesAsync();
	}

	public async Task<IEnumerable<Period>> GetListAsync(
		Expression<Func<Period, bool>> predicate)
	{
		return await this.context.Set<Period>()
			.Include("Pots.Expenses").Where(predicate).ToListAsync();
	}

	public async Task<Period> GetOneAsync(Guid id)
	{
		return await this.context.Set<Period>()
			.FirstOrDefaultAsync(x => x.Id == id);
	}

	public async Task UpdateAsync(Period updatedEntity)
	{
		this.context.Update(updatedEntity);
		await this.context.SaveChangesAsync();
	}
}