$[4$ pts$]$ Explain the role of 'callback' in the following Keras program code.

callback $=$ keras.callbacks.EarlyStopping$($monitor$=$'loss', patience$=3)$

history $=$ model.fit$($np$.$arange$(100).$reshape $(5,20),$ np$.$zeros$(5),$ epochs $=10,$ batch$\_$size $=1,$