module 'keras.backend' has no attribute 'symbolic'

Question

I am using Google Colab and installed the following libraies:

!pip3 install tensorflow==2.2
!pip3 install keras==2.3.1
!pip install keras_adamw

When I import "keras_adamw" I get this error:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-12-f0562343d039> in <module>()
----> 1 from keras_adamw import AdamW
/usr/local/lib/python3.7/dist-packages/keras_adamw/__init__.py in <module>()
     22 else:
     23     if TF_2 or KERAS_23:
---> 24         from .optimizers import AdamW, NadamW, SGDW
     25     else:
     26         from .optimizers_225 import AdamW, NadamW, SGDW

/usr/local/lib/python3.7/dist-packages/keras_adamw/optimizers.py in <module>()
     12
     13
---> 14 class AdamW(Optimizer):
     15     """AdamW optimizer.
     16     Default parameters follow those provided in the original paper.
/usr/local/lib/python3.7/dist-packages/keras_adamw/optimizers.py in AdamW()
     113 
     114     @interfaces.legacy_get_updates_support
-->  115     @K.symbolic
     116     def get_updates(self, loss, params):
     117         grads = self.get_gradients(loss, params)

AttributeError: module 'keras.backend' has no attribute 'symbolic'

I tried to search but I did not find any posts with similar error.