def _get_num_interval(config, num_pre, num_post):
 post = (int(num_post) if num_post else 0)
 pre = (int(num_pre) if (num_pre is not None) else _get_last_snapshot(config)['id'])
 return (pre, post)

def _get_num_interval ( config , num_pre , num_post ) : post = ( int ( num_post ) if num_post else 0 ) pre = ( int ( num_pre ) if ( num_pre is not None ) else _get_last_snapshot ( config ) [ 'id' ] ) return ( pre , post )
returns numerical interval based on optionals num_pre .