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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def create(self, validated_data):
 """Override ``create`` to provide a user via request.user by default. This is required since the read_only ``user`` field is not included by default anymore since https://github.com/encode/django-rest-framework/pull/5886. """

        if 'user' not in validated_data:
            validated_data['user'] = self.context['request'].user
        return super(RefreshTokenSerializer, self).create(validated_data)