gin-config keras bug

conf.gin

layers.Dense.kernel_regularizer = @regularizers.l2()
regularizers.l2.l = 1e-4

main.py

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import tensorflow as tf
import gin

# fails
Dense = tf.keras.layers.Dense
gin.config.external_configurable(Dense, module='layers')

# succeeds
# Dense = gin.config.external_configurable(tf.keras.layers.Dense, module='layers')

# succeeds
# @gin.configurable(module='layers')
# def Dense(units, kernel_regularizer=None):
#     return tf.keras.layers.Dense(units, kernel_regularizer=kernel_regularizer)


gin.config.external_configurable(
    tf.keras.regularizers.l2, module='regularizers')

gin.parse_config_files_and_bindings(['conf.gin'], [])

x = tf.zeros((5, 4))
layer = Dense(10)
layer(x)
print(layer.kernel_regularizer)

# Should work
Dense = tf.keras.layers.Dense
CDense = gin.config.external_configurable(Dense, module='layers')