def topk ( arg , k , by = None ) : op = ops . TopK ( arg , k , by = by ) return op . to_expr ( )
python pick top k
Returns ------- topk : TopK filter expression
def topk(arg, k, by=None):
    """
    Returns
    -------
    topk : TopK filter expression
    """
    op = ops.TopK(arg, k, by=by)
    return op.to_expr()