如何在Django Admin中添加占位符文本到搜索框？

from django.contrib import admin

class MyModelAdmin(admin.ModelAdmin):
    pass

from django.contrib import admin

class MyModelAdmin(admin.ModelAdmin):
    def get_search_results(self, request, queryset, search_term):
        # 设置搜索框的占位符文本
        self.search_placeholder = "请输入搜索关键字"
        return super().get_search_results(request, queryset, search_term)

from django.contrib import admin
from .models import MyModel

@admin.register(MyModel)
class MyModelAdmin(MyModelAdmin):
    pass