code: def s3_download(url, dst):  # type: (str, str) -> None
      
      url = parse.urlparse(url)
  
      if url.scheme != 's3':
          raise ValueError("Expecting 's3' scheme, got: %s in %s" % (url.scheme, url))
  
      bucket, key = url.netloc, url.path.lstrip('/')
  
      region = os.environ.get('AWS_REGION', os.environ.get(_params.REGION_NAME_ENV))
      s3 = boto3.resource('s3', region_name=region)
  
      s3.Bucket(bucket).download_file(key, dst)
docs: Download a file from S3.
  
      Args:
          url (str): the s3 url of the file.
          dst (str): the destination where the file will be saved.