Apply Selector Layer Principles in Apex

Apply Selector Layer Principles in Apex
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class name: AccountsSelector

public class AccountsSelector extends fflib_SObjectSelector {
	public List<Schema.SObjectField> getSObjectFieldList() {
             return new List<Schema.SObjectField> {
                Account.Name,
                Account.Description,
                Account.AnnualRevenue};
        }
        public Schema.SObjectType getSObjectType() {
             return Account.sObjectType;
        }
        public List<Account> selectById(Set<ID> idSet) {
             return (List<Account>) selectSObjectsById(idSet);
        }
  }