public async Task <Street> AddStreetAsync(string street)
        {
            var findedStreet = await Streets
                               .FirstOrDefaultAsync(m => m.StreetName.Equals(street, StringComparison.OrdinalIgnoreCase));

            if (findedStreet == null)
            {
                findedStreet = new Street
                {
                    StreetName = street
                };
                await AddAsync(findedStreet);
                await SaveChangesAsync();
            }

            return(findedStreet);
        }