code: def collect_non_report_files(args, discovered_files):
      
      excl_paths = exclude_paths(args)
      abs_root = os.path.abspath(args.root)
      non_report_files = []
      for root, dirs, files in os.walk(args.root, followlinks=args.follow_symlinks):
          dirs[:] = filter_dirs(root, dirs, excl_paths)
  
          for filename in files:
              if not is_source_file(args, filename):
                  continue
              abs_filepath = os.path.join(os.path.abspath(root), filename)
              if is_excluded_path(args, abs_filepath):
                  continue
              filepath = os.path.relpath(abs_filepath, abs_root)
              if filepath not in discovered_files:
                  src_report = {}
                  src_report['name'] = posix_path(filepath)
                  coverage = []
                  with io.open(abs_filepath, mode='rb') as fobj:
                      for _ in fobj:
                          coverage.append(None)
                      fobj.seek(0)
                      src_report['source_digest'] = hashlib.md5(fobj.read()).hexdigest()
                  src_report['coverage'] = coverage
                  non_report_files.append(src_report)
      return non_report_files
docs: Collects the source files that have no coverage reports.