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 from django.contrib.auth import authenticate  
from rest_framework import serializers  
  
  
class AuthTokenSerializer(serializers.Serializer):  
    username = serializers.CharField()  
    password = serializers.CharField()  
  
    def validate(self, attrs):  
        username = attrs.get('username')  
        password = attrs.get('password')  
  
        if username and password:  
            user = authenticate(username=username, password=password)  
  
            if user:  
                if not user.is_active:  
                    raise serializers.ValidationError('User account is disabled.')  
                attrs['user'] = user  
                return attrs  
            else:  
                raise serializers.ValidationError('Unable to login with provided credentials.')  
        else:  
            raise serializers.ValidationError('Must include "username" and "password"')  
                
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