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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def train_default_model():
 """Function for training the default NER model. NB! It overwrites the default model, so do not use it unless you know what are you doing. The training data is in file estnltk/corpora/estner.json.bz2 . The resulting model will be saved to estnltk/estner/models/default.bin """

    docs = read_json_corpus(DEFAULT_NER_DATASET)
    trainer = NerTrainer(default_nersettings)
    trainer.train(docs, DEFAULT_NER_MODEL_DIR)