code: def amazon_s3(self, scene, bands):
          
  
          sat = self.scene_interpreter(scene)
  
          # Always grab MTL.txt and QA band if bands are specified
          if 'BQA' not in bands:
              bands.append('QA')
  
          if 'MTL' not in bands:
              bands.append('MTL')
  
          urls = []
  
          for band in bands:
              # get url for the band
              url = self.amazon_s3_url(sat, band)
  
              # make sure it exist
              self.remote_file_exists(url)
              urls.append(url)
  
          # create folder
          path = check_create_folder(join(self.download_dir, scene))
  
          self.output('Source: AWS S3', normal=True, arrow=True)
          for url in urls:
              self.fetch(url, path)
  
          return path
docs: Amazon S3 downloader