Return attributes that should be part of the repr string.

def _repr_attributes(self):
        """Return attributes that should be part of the repr string."""
        if self._repr_attributes_override is None:
            # Default to init arguments
            attrs = getfullargspec(self.__init__).args[1:]
            mapping = self._repr_attributes_mapping
            if mapping:
                attrs = [mapping[a] if a in mapping else a for a in attrs]
            return attrs

        return self._repr_attributes_override