Convert attribute definition into a dictionary.

        Returns
        -------
        dict
            Json-like dictionary representation of the attribute definition

def to_dict(self):
        """Convert attribute definition into a dictionary.

        Returns
        -------
        dict
            Json-like dictionary representation of the attribute definition
        """
        obj = {
            'id' : self.identifier,
            'name' : self.name,
            'description' : self.description,
            'type' : self.data_type.to_dict()
        }
        if not self.default is None:
            obj['default'] = self.default
        return obj