Rock.Model.GroupMemberService.GetFirstNames C# (CSharp) Method

        public IEnumerable<string> GetFirstNames( int groupId, bool includeDeceased = false )
        {
            return GetByGroupId(groupId, includeDeceased).
                OrderBy( m => m.GroupRole.Order ).
                ThenBy( m => m.Person.BirthYear ).ThenBy( m => m.Person.BirthMonth ).ThenBy( m => m.Person.BirthDay ).
                ThenBy( m => m.Person.Gender ).
                Select( m => m.Person.NickName ).
                ToList();
        }

        /// <summary>
        /// Executes the specified workflow.
        /// </summary>
        /// <param name="action">The workflow action.</param>
        /// <param name="entity">The entity.</param>
        /// <param name="errorMessages">The error messages.</param>
        /// <returns></returns>
        /// <exception cref="System.NotImplementedException"></exception>
        public override bool Execute( Model.WorkflowAction action, Object entity, out List<string> errorMessages )
        {
            var checkInState = GetCheckInState( entity, out errorMessages );
            if (checkInState != null)
            {
                using ( new Rock.Data.UnitOfWorkScope() )
                {
                    var personService = new PersonService();
                    var memberService = new GroupMemberService();
                    IQueryable<Person> people = null;

                    if ( checkInState.CheckIn.SearchType.Guid.Equals( new Guid( SystemGuid.DefinedValue.CHECKIN_SEARCH_TYPE_PHONE_NUMBER ) ) )
                    {
                        people = personService.GetByPhonePartial( checkInState.CheckIn.SearchValue );
                    }
                    else if ( checkInState.CheckIn.SearchType.Guid.Equals( new Guid( SystemGuid.DefinedValue.CHECKIN_SEARCH_TYPE_NAME ) ) )
                    {
                        people = personService.GetByFullName( checkInState.CheckIn.SearchValue );
                    }
                    else
                    {
                        errorMessages.Add( "Invalid Search Type" );
                        return false;
                    }

                    foreach ( var person in people.ToList() )
                    {
                        foreach ( var group in person.Members.Where( m => m.Group.GroupType.Guid == new Guid( SystemGuid.GroupType.GROUPTYPE_FAMILY ) ).Select( m => m.Group ).ToList() )
                        {
                            var family = checkInState.CheckIn.Families.Where( f => f.Group.Id == group.Id ).FirstOrDefault();
                            if ( family == null )
                            {
                                family = new CheckInFamily();
                                family.Group = group.Clone( false );
                                family.Group.LoadAttributes();
                                family.Caption = group.ToString();
                                family.SubCaption = memberService.GetFirstNames( group.Id ).ToList().AsDelimited( ", " );
                                checkInState.CheckIn.Families.Add( family );
                            }
                        }
                    }

                    return true;
                }
            }

            errorMessages.Add( "Invalid Check-in State" );
            return false;
        }