def layer_output(model, layer_name=None):
	"""Output tensor of a specific layer in a model.

	"""
	conv_index = -1

	for i in range(len(model.layers) - 1, -1, -1):
		layer = model.layers[i]
		if layer_name in layer.name:
			conv_index = i
			break

	if conv_index < 0:
		print('Error: could not find the interested layer.')

	return model.layers[conv_index].output