title: ImportError: cannot import name 'K' from 'keras.layers'
body: <p>my tensorflow version is 2.4.0, and keras version is 2.4.3, when I do <code>from keras.layers import K</code>, the error occured, <code>ImportError: cannot import name 'K' from 'keras.layers' </code>. I think it must be version issue, but how can I change to a right Keras version?</p>