Django: Admin: changing the widget of the field in Admin

UPDATE 1: Code that gets me done with 1) (don’t forget tot pass CHOICES to the BooleanField in the model)

from main.models import TagCat
from django.contrib import admin
from django import forms

class MyTagCatAdminForm(forms.ModelForm):
    class Meta:
        model = TagCat
        widgets = {
            'by_admin': forms.RadioSelect
        }
        fields="__all__" # required for Django 3.x
    
class TagCatAdmin(admin.ModelAdmin):
    form = MyTagCatAdminForm


admin.site.register(TagCat, TagCatAdmin)

The radio buttons appear ugly and displaced, but at least, they work

2. I solved with following info in MyModel.py:

BYADMIN_CHOICES = (
    (1, "Yes"),
    (0, "No"),
)

class TagCat(models.Model):
    by_admin = models.BooleanField(choices=BYADMIN_CHOICES,default=1)