public boolean isSectionCollapsed(int sectionIndex) {
        if (collapsedSections.containsKey(sectionIndex)) {
            return collapsedSections.get(sectionIndex);
        }

        return false;
    }
@param sectionIndex index of section
@return true if that section is collapsed
android/modules/module_common/src/main/java/github/tornaco/android/thanos/widget/section/SectioningAdapter.java