old_contents: from . import cuda, cudnn
  from .variable import Variable
  from .function import Function
  from .function_set import FunctionSet
  from .optimizer import Optimizer
  
  from .functions import basic_math  # Install variable operators
  
new_contents: from chainer import function
  from chainer import function_set
  from chainer.functions import basic_math  # Install variable operators
  from chainer import optimizer
  from chainer import variable
  
  Variable = variable.Variable
  Function = function.Function
  FunctionSet = function_set.FunctionSet
  Optimizer = optimizer.Optimizer
  
subject: Fix __init__.py