Abstract: A method for training a machine learning model includes receiving a randomly-initialized first version of a machine learning model, conducting first training on the machine learning model first version using first training data, the first training data comprising a first type of information respective of a plurality of documents, adding a layer to the machine learning model first version after conducting the first training to create a machine learning model second version, and conducting second training on the machine learning model second version using second training data, the second training data comprising a second type of information respective of the plurality of documents.