def size(self, source):
    '''Get the size component of the given s3url. If it is a
       directory, combine the sizes of all the files under
       that directory. Subdirectories will not be counted unless
       --recursive option is set.
    '''
    result = []
    for src in self.source_expand(source):
      size = 0
      for f in self.s3walk(src):
        size += f['size']
      result.append((src, size))

    return result
Get the size component of the given s3url. If it is a
       directory, combine the sizes of all the files under
       that directory. Subdirectories will not be counted unless
       --recursive option is set.