Password validation not work in django-rest-framework

when I register new user at that time password validator not work.(e.g. When I enter admin123 and password is also admin123 at that time password validator not saw like this error: password must not same as username.)

serializer.py:

from rest_framework import serializers
from django.contrib.auth import get_user_model

User = get_user_model()

class SignUpSerializer(serializers.ModelSerializer):
    
    class Meta:
        model = User
        fields = ['username','email','password']
        write_only_fields = ('password',)
        read_only_fields = ('id',)

views.py:

from rest_framework import status
from django.contrib.auth import get_user_model
from .serializers import SignUpSerializer
from rest_framework.decorators import api_view, permission_classes
from rest_framework.response import Response
from rest_framework.permissions import AllowAny
from django.contrib.auth.password_validation import validate_password
from django.core.exceptions import ValidationError

User = get_user_model()

@api_view(['POST'])
@permission_classes([AllowAny,])
def signup(request):
    serializer = SignUpSerializer(data=request.data)
    
    if serializer.is_valid():
        username = serializer.data['username']
        
        try:
            validate_password(serializer.data['password'], username)
        except ValidationError as e:
            return Response(str(e), status=status.HTTP_400_BAD_REQUEST)
        
        user = User(
            username = username,
            email = serializer.data['email']
        )
        user.set_password(serializer.data['password'])
        user.save()
        return Response(serializer.data, status=status.HTTP_201_CREATED)
    else:
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

settings.py

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]