'Return a list of (points, max_points) tuples representing the
aggregate score for the section.
Example:
page.section_score(\'Week 1\', \'Lesson 1\') --> (2, 5)
Returns `None` if no such chapter and section can be found.'

def section_score(self, chapter, section):

    chapter_index = self._chapter_index(chapter)
    if (chapter_index is None):
        return None
    section_index = self._section_index(chapter_index, section)
    if (section_index is None):
        return None
    return self._aggregate_section_score(chapter_index, section_index)
