You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: stream_commands.go
    path of file: ./repos/streamdal/apps/server/vendor/github.com/redis/go-redis/v9
    
    the code of the file until where you have to start completion: package redis

import (
	"context"
	"time"
)

type StreamCmdable interface {
	XAdd(ctx context.Context, a *XAddArgs) *StringCmd
	XDel(ctx context.Context, stream string, ids ...string) *IntCmd
	XLen(ctx context.Context, stream string) *IntCmd
	XRang
    
func (c cmdable) XPendingExt(ctx context.Context, a *XPendingExtArgs) *XPendingExtCmd {
	args := make([]interface{}, 0, 9)
	args = append(args, "xpending", a.Stream, a.Group)
	if a.Idle != 0 {
		args = append(args, "idle", formatMs(ctx, a.Idle))
	}
	args = append(args, a.Start, a.End, a.Count)
	if a.Consumer != "" {
		args = append(args, a.Consumer)
	}
	cmd := NewXPendingExtCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}