Output tensors of a Functional model must be the output of a TensorFlow `Layer` (thus holding past layer metadata).

 

ValueError: Output tensors of a Functional model must be the output of a TensorFlow `Layer` (thus holding past layer metadata). Found: <tensorflow.python.keras.layers.convolutional.Conv2D object at 0x7fb0bb908850>

Do not forget to give the previous layer as a parameter in current layer. If the chain is broken, you will get the above error