Add name variant.

        Args:
            :param name: name variant for the current author.
            :type name: string

def add_name_variant(self, name):
        """Add name variant.

        Args:
            :param name: name variant for the current author.
            :type name: string
        """
        self._ensure_field('name', {})
        self.obj['name'].setdefault('name_variants', []).append(name)