restframework 'tuple' object has no attribute '_meta'

Just wanted to add a potential case where such a thing might happen. In case you are using get_or_create, keep in mind that this method returns a tuple, and not just the object.

As an example:

book = Book.objects.get_or_create(pk=123)
serializer = BookSerializer(book, request.data)
if serializer.is_valid():
    serializer.save() # <-- Right here you would get the same error 

The problem is fixed by unpacking the tuple:

book, created = Book.objects.get_or_create(pk=123)

# or this way if you do not need to know if it was created or not
book, _ = Book.objects.get_or_create(pk=123)

You are having the , after the name of BDetail model in BDetailSerializer serializer. Remove that and your code will work.

Suggestion: Inherit serializers.ModelSerializer in your BDetailSerializer serializer instead of serializers.HyperlinkedModelSerializer i.e. :

class BDetailSerializer(serializers.ModelSerializer):
    class Meta:
        model = BDetail
        fields = ('lat', 'lng')