Throws an error if the course_elements selector is an empty list.
Throws error in course_attribute_elements selector is empty list.
Factored out the paginator variable.
Factored out get_next_page method. Renamed get_courses to parse_page.
Added WebPageChangedError exception class.
Now checks for paginator, number_of_pages, and current_page selector
errors as well.
Refactored to stay within 79 chars/line limit.
Factored out the extract_fields method.
Checks for IndexErrors in elements of fields selectors.
Creates results director if it does not exist.