'Sets up and returns XML course structure.'

@staticmethod
def _set_up_course_xml():

    course = xml.CourseFactory.build(end=str(COURSE_END_DATE))
    chapter_1 = xml.ChapterFactory.build(parent=course)
    xml.ChapterFactory.build(parent=course)
    chapter_3 = xml.ChapterFactory.build(parent=course)
    chapter_4 = xml.ChapterFactory.build(parent=course)
    xml.SequenceFactory.build(parent=chapter_1)
    xml.SequenceFactory.build(parent=chapter_1)
    sequence_3_1 = xml.SequenceFactory.build(parent=chapter_3)
    xml.SequenceFactory.build(parent=chapter_4, hide_after_due=str(True), due=str(DUE_DATE))
    for _ in range(3):
        xml.VerticalFactory.build(parent=sequence_3_1)
    return course
