code: def prepare_date(data, date_column):
      data[date_column] = pd.to_datetime(data[date_column])
      index = pd.DatetimeIndex(data[date_column])
      data["year"] = index.year
      data["month"] = index.month
      data["day"] = index.day
      return data
  
file_path: h2o-3/h2o-py/tests/testdir_algos/gbm/pyunit_PUBDEV_4076_custom_distribution_demo.py
imports: import sys
  import h2o
  from tests import pyunit_utils
  import pandas
  from h2o.estimators.gbm import H2OGradientBoostingEstimator
  from h2o.utils.distributions import CustomDistributionGaussian
label_desc: Use image node_id 1 for calling a global function with example usage: prepare_date(data, date_column) and returns: data