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# Language: Python

# Import required modules
from rest_framework import generics
from rest_framework.response import Response
from rest_framework import status
from .serializers import ModelSerializer
from .models import Model
from .repositories import ModelRepository

# Create repository object
model_repository = ModelRepository()

class ModelListView(generics.ListCreateAPIView):
    """
    List all models or create a new model
    """
    # Define serializer class
    serializer_class = ModelSerializer

    def get(self, request, *args, **kwargs):
        """
        Return a list of all models
        """
        # Fetch models from the repository
        models = model_repository.list_models()
        # Serialize the models
        serializer = ModelSerializer(models, many=True)
        # Return the serialized models
        return Response(serializer.data)

    def post(self, request, *args, **kwargs):
        """
        Create a new model
        """
        # Deserialize the request data
        serializer = ModelSerializer(data=request.data)
        # If the data is valid
        if serializer.is_valid():
            # Create the new model
            model = model_repository.create_model(serializer.data)
            # If the model creation was successful
            if model:
                # Serialize the model
                serializer = ModelSerializer(model)
                # Return the serialized model
                return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

class ModelDetailView(generics.RetrieveUpdateDestroyAPIView):
    """
    Retrieve, update or delete a model instance
    """
    # Define serializer class
    serializer_class = ModelSerializer

    def get(self, request, *args, **kwargs):
        """
        Retrieve a model by ID
        """
        # Fetch the model from the repository
        model = model_repository.get_model(kwargs['pk'])
        # If the model exists
        if model:
            # Serialize the model
            serializer = ModelSerializer(model)
            # Return the serialized model
            return Response(serializer.data, status=status.HTTP_200_OK)
        return Response(status=status.HTTP_404_NOT_FOUND)

    def put(self, request, *args, **kwargs):
        """
        Update a model by ID
        """
        # Fetch the model from the repository
        model = model_repository.get_model(kwargs['pk'])
        # If the model exists
        if model:
            # Deserialize the request data
            serializer = ModelSerializer(model, data=request.data)
            # If the data is valid
            if serializer.is_valid():
                # Update the model
                model = model_repository.update_model(serializer.validated_data)
                # If the update was successful
                if model:
                    # Serialize the updated model
                    serializer = ModelSerializer(model)
                    # Return the serialized model
                    return Response(serializer.data, status=status.HTTP_200_OK)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    def delete(self, request, *args, **kwargs):
        """
        Delete a model by ID
        """
        # Fetch the model from the repository
        model = model_repository.get_model(kwargs['pk'])
        # If the model exists
        if model:
            # Delete the model
            model_repository.delete_model(model)
            return Response(status=status.HTTP_204_NO_CONTENT)
        return Response(status=status.HTTP_404_NOT_FOUND)

In this code, we have implemented CRUD (Create, Read, Update, Delete) for a Model in DRF (Django Rest Framework) using repository service pattern. The repository pattern encapsulates the logic of data access and management from the other parts of the application.

We have created a ModelListView and ModelDetailView, which allow the user to list all the models, create a new model, retrieve, update or delete a model instance. These views inherit from DRF's ListCreateAPIView and RetrieveUpdateDestroyAPIView classes, which provide boilerplate code for standard GET, POST, PUT and DELETE requests.

In this code, we have also created a ModelRepository class, which is responsible for reading/writing data from/to the database. The ModelRepository includes functionality such as creating a new model, fetching a single model by ID, updating a model, deleting a model and fetching all the models.

We have also used ModelSerializer to read/write data from/to the database. The data serializers provide a way of translating complex data types, such as django models, into python data types that can be easily rendered into JSON/XML content.