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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 prepare_data():
 """Load and normalize data."""

  ((x_train, y_train), (x_test, y_test)) = DATASET.load_data()
  x_train = x_train.astype("float32")
  x_test = x_test.astype("float32")
  x_train /= 255.0
  x_test /= 255.0
  return ((x_train, y_train), (x_test, y_test))