code: def _todense(data):
      X_train, y_train, X_test, y_test = data
      X_train = X_train.toarray()
      if X_test is not None:
          X_test = X_test.toarray()
      return X_train, y_train, X_test, y_test
  
imports: import os
  import numpy
  import scipy.sparse
  from sklearn.datasets.base import get_data_home
  from sklearn.utils import check_random_state
label_desc: Use image node_id 3 for calling a global function with example usage: _todense(data) and returns: X_train,  y_train,  X_test,  y_test