Attempt at a user serializer in DRF 3.0

user_serializer.py

class UserSerializer(serializers.ModelSerializer):
    password = serializers.CharField(
      min_length=6, write_only=True, required=False)

    class Meta:
        model = User
        fields = ('id', 'first_name', 'last_name', 'password')

    def create(self, validated_data):
        password = validated_data.pop('password', None)
        user = User.objects.create(**validated_data)
        if password is not None:
            user.set_password(password)
            user.save()
        return user

    def update(self, instance, validated_data):
        instance.first_name = validated_data['first_name']
        instance.last_name = validated_data['last_name']
        password = validated_data.get('password', None)
        if password is not None:
            instance.set_password(password)
        instance.save()
        return instance