keras/src/layers/preprocessing/index_lookup.py/IndexLookup/_uninitialized_lookup_table
class IndexLookup:    def _uninitialized_lookup_table(self):
        with tf.init_scope():
            initializer = get_null_initializer(
                self._key_dtype, self._value_dtype
            )
            return tf.lookup.StaticHashTable(initializer, self._default_value)