Different name of serializer data django

I want to serializer a list of dicts that contain a whitespace.
Obviously I can't write cat name = serializer.Charfield(...) in Python
(see the space between the and cat).

So, I tried source=, but I get an error.

{ "cat_name": [ "This field is required." ] }

Here's my code:

class MySerializer(serializers.Serializer):
    cat_name = serializers.CharField(source='Cat name')

s = MySerializer(data={'Cat name': 'Smith'})
s.is_valid(raise_exception=True)

What am I doing wrong?

Note that this can't change:

data={'Cat name': 'Smith'}

You can make a mixin that translates keys to values, like:

class TranslateMixin:
    translation = {}
    _reverse_translation = None

    @property
    def reverse_translation(self):
        if self._reverse_translation is None:
            type(self)._reverse_translation = {
                v: k for k, v in self.translation.items()
            }
        return self._reverse_translation

    def to_internal_value(self, data):
        super().to_internal_value(
            {self.translation.get(k, k): v for k, v in data.items()}
        )

    def to_representation(self, instance):
        result = super().to_representation(instance)
        return {self.reverse_translation.get(k, k): v for k, v in result.items()}

and then define a translation with:

class MySerializer(TranslateMixin, serializers.Serializer):
    cat_name = serializers.CharField()
    translation = {'Cat name': 'cat_name'}

This will thus pre-process the items when you use the serializer to generate instances, and post-process in reverse when you serialize instances.

I would however advise not to use spaces in field names, not at the JavaScript side either. Since fields with spaces can not act as identifiers, it makes code a lot more complicated.