How to get Request.User in Django-Rest-Framework serializer?

I’ve tried something like this, it does not work.

class PostSerializer(serializers.ModelSerializer):

    class Meta:
        model = Post

    def save(self):
        user = self.context['request.user']
        title = self.validated_data['title']
        article = self.validated_data['article']

I need a way of being able to access request.user from my Serializer class.