code: def get_files(self, is_dl_forced, files=None):
          
  
          fstat = None
          if files is None:
              files = self.files
          for fname in files:
              LOG.info("Getting %s", fname)
              headers = None
              filesource = files[fname]
              if 'headers' in filesource:
                  headers = filesource['headers']
              self.fetch_from_url(
                  filesource['url'], '/'.join((self.rawdir, filesource['file'])),
                  is_dl_forced, headers)
              # if the key 'clean' exists in the sources `files` dict
              # expose that instead of the longer url
              if 'clean' in filesource and filesource['clean'] is not None:
                  self.dataset.setFileAccessUrl(filesource['clean'])
              else:
                  self.dataset.setFileAccessUrl(filesource['url'])
  
              fstat = os.stat('/'.join((self.rawdir, filesource['file'])))
  
          # only keeping the date from the last file
          filedate = datetime.utcfromtimestamp(fstat[ST_CTIME]).strftime("%Y-%m-%d")
  
          # FIXME
          # change this so the date is attached only to each file, not the entire dataset
          self.dataset.set_date_issued(filedate)
docs: Given a set of files for this source, it will go fetch them, and
          set a default version by date.  If you need to set the version number
          by another method, then it can be set again.
          :param is_dl_forced - boolean
          :param files dict - override instance files dict
          :return: None