With tf.keras.callbacks.ModelCheckpoint, what are the valid string values for the ‘monitor’ argument?

Using the following link: https://www.tensorflow.org/api_docs/python/tf/keras/callbacks/ModelCheckpoint?version=stable I am unable to determine the valid argument inputs for the monitor argument. By default it is set as ‘val_loss’. Where can I find the list of acceptable inputs for this argument? With more context to my problem, I am trying to set a checkpoint that saves the “best” model…

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Downloaded blockchain using Bitcoin-qt with unpurned mode, but bitcoind told me it’s purned

I synced the blockchain in unpurned mode (it is 299 GB currently) when first open bitcoin core via bitcoin-qt. And I can run console scripts in bitcoin-qt ‘s debug window normally. But when I open the bitcoind, it shows me this 2019-12-20T11:53:41Z Bitcoin Core version v0.19.0.1 (release build) 2019-12-20T11:53:41Z Assuming ancestors of block 00000000000000000005f8920febd39 25f8272a6a71237563d78c2edfdd09ddf…

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