@NotNull
  private static List<PyRequirement> parseRecursiveLine(@NotNull String line,
                                                        @Nullable VirtualFile containingFile,
                                                        @NotNull Set<VirtualFile> visitedFiles,
                                                        int flagLength) {
    if (containingFile == null) return Collections.emptyList();

    final int pathIndex = findFirstNotWhiteSpaceAfter(line, flagLength);
    if (pathIndex == line.length()) return Collections.emptyList();

    final String path = FileUtil.toSystemIndependentName(line.substring(pathIndex));
    final VirtualFile file = findRecursiveFile(containingFile, path);

    if (file != null && !visitedFiles.contains(file)) {
      return fromText(loadText(file), file, visitedFiles);
    }

    return Collections.emptyList();
  }
@NotNull
  private static List<PyRequirement> parseRecursiveLine(@NotNull String line,
                                                        @Nullable VirtualFile containingFile,
                                                        @NotNull Set<VirtualFile> visitedFiles,
                                                        int flagLength)