Prompt Title: improve method

how can i make this method more efficient public async Task<TaskPatternDto[]> Handle(GetTaskPatternQuery query, CancellationToken cancellationToken) { var filteredPatterns = new List<List<TaskPatternDto>>(); query.MachineIds = query.MachineIds.Distinct().ToArray(); _validator.ValidateAndThrow(query); try { var entities = _context.Pattern .WhereIf(query.PatternId.HasValue, x => x.PatternId == query.PatternId) .WhereIf(query.IstStatic.HasValue, x => x.isStatic == query.IstStatic); var dto = (await Task.FromResult(_mapper.Map<TaskPatternDto[]>(entities))).ToList(); query.MachineIds.ToList().ForEach( x => { var filtered = dto.Where(p => p.MachineId == x).ToList(); filteredPatterns.Add(filtered); }); var flatterned = filteredPatterns.SelectMany(i => i); flatterned.ToList().ForEach(x => { if (_context.ScheduledTask.Where(e => e.PatternId == x.PatternId).Any()) x.PatternType = 1; else x.PatternType = 2; }); return flatterned.ToArray(); } catch (Exception ex) { throw new Exception(GetType().Name, ex); } }