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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_input_fn(params):
 """Load and return dataset of batched examples for use during training."""

  file_pattern = os.path.join(getattr(params, "data_dir", ""), "*encoded-train*")
  return _read_and_batch_from_files(
      file_pattern, params.batch_size, params.max_length, params.num_cpu_cores,
      shuffle=True, repeat=params.repeat_dataset)