TODO: Document.

def get_qualification_requests(self, qualification_type_id,
                                   sort_by='Expiration',
                                   sort_direction='Ascending', page_size=10,
                                   page_number=1):
        """TODO: Document."""
        params = {'QualificationTypeId' : qualification_type_id,
                  'SortProperty' : sort_by,
                  'SortDirection' : sort_direction,
                  'PageSize' : page_size,
                  'PageNumber' : page_number}
        return self._process_request('GetQualificationRequests', params,
                    [('QualificationRequest', QualificationRequest),])