public Customer GetCustomer(Guid guid) => TakingCareOf.SingleOrDefault(x => x.Customer.Guid == guid)?.Customer;
public bool IsTakingCareOf(Guid customer) { return(TakingCareOf.Any(x => x.Customer.Guid == customer)); }
public Customer GetCustomer(string username) => TakingCareOf.SingleOrDefault(x => x.Customer.Username == username)?.Customer;
public bool IsTakingCareOf(string customerUsername) { return(TakingCareOf.Any(x => x.Customer.Username == customerUsername)); }