old_contents: # coding: utf-8
  """LightGBM, Light Gradient Boosting Machine.
  
  Contributors: https://github.com/microsoft/LightGBM/graphs/contributors.
  """
  from __future__ import absolute_import
  
  from .basic import Booster, Dataset
  from .callback import (early_stopping, print_evaluation, record_evaluation,
                         reset_parameter)
  from .engine import cv, train, CVBooster
  
  import os
  
  try:
      from .sklearn import LGBMModel, LGBMRegressor, LGBMClassifier, LGBMRanker
  except ImportError:
      pass
  try:
      from .plotting import (plot_importance, plot_split_value_histogram, plot_metric,
                             plot_tree, create_tree_digraph)
  except ImportError:
      pass
  
  
  dir_path = os.path.dirname(os.path.realpath(__file__))
  
  if os.path.isfile(os.path.join(dir_path, 'VERSION.txt')):
      with open(os.path.join(dir_path, 'VERSION.txt')) as version_file:
          __version__ = version_file.read().strip()
  
  __all__ = ['Dataset', 'Booster', 'CVBooster',
             'train', 'cv',
             'LGBMModel', 'LGBMRegressor', 'LGBMClassifier', 'LGBMRanker',
             'print_evaluation', 'record_evaluation', 'reset_parameter', 'early_stopping',
             'plot_importance', 'plot_split_value_histogram', 'plot_metric', 'plot_tree', 'create_tree_digraph']
  
new_contents: # coding: utf-8
  """LightGBM, Light Gradient Boosting Machine.
  
  Contributors: https://github.com/microsoft/LightGBM/graphs/contributors.
  """
  from __future__ import absolute_import
  
  from .basic import Booster, Dataset
  from .callback import (early_stopping, print_evaluation, record_evaluation,
                         reset_parameter)
  from .engine import cv, train, CVBooster
  
  import os
  import sys
  import warnings
  
  try:
      from .sklearn import LGBMModel, LGBMRegressor, LGBMClassifier, LGBMRanker
  except ImportError:
      pass
  try:
      from .plotting import (plot_importance, plot_split_value_histogram, plot_metric,
                             plot_tree, create_tree_digraph)
  except ImportError:
      pass
  
  
  dir_path = os.path.dirname(os.path.realpath(__file__))
  
  if os.path.isfile(os.path.join(dir_path, 'VERSION.txt')):
      with open(os.path.join(dir_path, 'VERSION.txt')) as version_file:
          __version__ = version_file.read().strip()
  
  __all__ = ['Dataset', 'Booster', 'CVBooster',
             'train', 'cv',
             'LGBMModel', 'LGBMRegressor', 'LGBMClassifier', 'LGBMRanker',
             'print_evaluation', 'record_evaluation', 'reset_parameter', 'early_stopping',
             'plot_importance', 'plot_split_value_histogram', 'plot_metric', 'plot_tree', 'create_tree_digraph']
  
  # REMOVEME: remove warning after 3.1.0 version release
  if sys.version_info[0] == 2:
      warnings.warn("LightGBM 3.1 version is the last version that supports Python 2.\n"
                    "Next release will drop the support.", UserWarning)
  
subject: mark 3.1 version is the last one with Python 2 support (#3565)