Look up up an item in the cache and return a line iterator.
        The underlying file will be closed once all lines have been
        consumed.

def load_lines(self, key, noexpire=None):
        '''Look up up an item in the cache and return a line iterator.
        The underlying file will be closed once all lines have been
        consumed.'''
        return line_iterator(self.load_fd(key, noexpire=noexpire))