code: def get_dates_for_project(self, project):
          file_re = re.compile(r'^%s_([0-9]{8})\.json$' % project)
          all_dates = []
          for f in os.listdir(self.cache_path):
              if not os.path.isfile(os.path.join(self.cache_path, f)):
                  continue
              m = file_re.match(f)
              if m is None:
                  continue
              all_dates.append(datetime.strptime(m.group(1), '%Y%m%d'))
          return sorted(all_dates)