@NotNull
  private static List<PyRequirement> parseLine(@NotNull String line,
                                               @Nullable VirtualFile containingFile,
                                               @NotNull Set<VirtualFile> visitedFiles) {
    if (line.startsWith("-r")) {
      return parseRecursiveLine(line, containingFile, visitedFiles, "-r".length());
    }

    if (line.startsWith("--requirement ")) {
      return parseRecursiveLine(line, containingFile, visitedFiles, "--requirement ".length());
    }

    return Collections.singletonList(fromLine(line));
  }
@NotNull
  private static List<PyRequirement> parseLine(@NotNull String line,
                                               @Nullable VirtualFile containingFile,
                                               @NotNull Set<VirtualFile> visitedFiles)