private static Set<InternalIdeaSourceDirectory> readSourceDirectories(IonReader reader, String fieldName) {
    IonType ionType = reader.next();
    if (fieldName != null) {
      assertFieldName(reader, fieldName);
    }
    if (ionType == IonType.NULL || ionType == null) {
      return null;
    }

    reader.stepIn();
    Set<InternalIdeaSourceDirectory> sourceDirectories = new LinkedHashSet<>();
    InternalIdeaSourceDirectory sourceDirectory;
    while ((sourceDirectory = readSourceDirectory(reader)) != null) {
      sourceDirectories.add(sourceDirectory);
    }
    reader.stepOut();
    return sourceDirectories;
  }
private static Set<InternalIdeaSourceDirectory> readSourceDirectories(IonReader reader, String fieldName)