Name 'myCallback' is not defined error

When I run the notebook, every single test is being passed, but then it says that there is an error:
name ‘myCallback’ is not defined. The code looks fine to me, please help me debug the error

[code removed - moderator]

Notebook metadata is corrupt. Please refresh your workspace and try again.
See Refresh your Lab Workspace section here

I tried refreshing the Lab workspace, but it still says ‘myCallback’ is not defined error. Is there anything else I’m doing wrong in the submission, Sir?

Please click my name and message your notebook as an attachment.

The assignment starter code contains this:

class myCallback(tf.keras.callbacks.Callback):
    def on_epoch_end(self, epoch, logs={}):
        if logs.get('accuracy') is not None and logs.get('accuracy') > 0.999:
            print("\nReached 99.9% accuracy so cancelling training!")
            self.model.stop_training = True

Your notebook contains this:

class myCallback(tf.keras.callbacks.Callback):
    def on_epoch_end(self, epoch, logs={}):
        if(logs.get('acc')>DESIRED_ACCURACY):
            print("\nReached 99.9% accuracy so cancelling training!")
            self.model.stop_training = True

There’s no definition of DESIRED_ACCURACY:

Please reset the workspace and try again. If you see something wrong, remove the assignment starter file and then reset the workspace.