train_and_evaluateTrainSpec determines the input data for the training, as well as the
duration. Optional hooks run at various stages of training.
train_spec(input_fn, max_steps = NULL, hooks = NULL)Training input function returning a tuple of:
features - Tensor or dictionary of string feature name to Tensor.
labels - Tensor or dictionary of Tensor with labels.
Positive number of total steps for which to train model.
If NULL, train forever. The training input_fn is not expected to
generate OutOfRangeError or StopIteration exceptions.
List of session run hooks to run on all workers (including chief) during training.
Other training methods: eval_spec,
train_and_evaluate.tf_estimator