public List<string> Parse(List<string> files)
{
List<string> filesWithSearchPattern = files.FindAll(x => x.Contains(XlsSearchPattern) || x.Contains(XlsxSearchPattern));
List<string> completeListOfFiles = files.FindAll(x => !x.Contains(XlsSearchPattern) && !x.Contains(XlsxSearchPattern));
foreach (string file in filesWithSearchPattern)
{
completeListOfFiles.AddRange(GetFiles(file));
}
return completeListOfFiles;
}