old_contents: from chainer import cuda
  from chainer import function
  from chainer import utils
  from chainer.utils import type_check
  
  
  class Square(function.Function):
  
      @property
      def label(self):
          return 'square'
  
      def check_type_forward(self, in_types):
          type_check.expect(
              in_types.size() == 1,
              in_types[0].dtype.kind == 'f',
          )
  
      def forward(self, x):
          xp = cuda.get_array_module(*x)
          return utils.force_array(xp.square(x[0], dtype=x[0].dtype)),
  
      def backward(self, x, gy):
          gx = gy[0] * 2.0 * x[0]
          return utils.force_array(gx, dtype=x[0].dtype),
  
  
  def square(x):
      """Elementwise square function.
  
      .. math::
         y_i = x_i ^ 2.
  
      Args:
          x (~chainer.Variable): Input variable., :class:`numpy.ndarray` or
              :class:`cupy.ndarray` objects.
  
      Returns:
          ~chainer.Variable: Output variable.
      """
      return Square()(x)
  
new_contents: from chainer import cuda
  from chainer import function
  from chainer import utils
  from chainer.utils import type_check
  
  
  class Square(function.Function):
  
      @property
      def label(self):
          return 'square'
  
      def check_type_forward(self, in_types):
          type_check.expect(
              in_types.size() == 1,
              in_types[0].dtype.kind == 'f',
          )
  
      def forward(self, x):
          xp = cuda.get_array_module(*x)
          return utils.force_array(xp.square(x[0], dtype=x[0].dtype)),
  
      def backward(self, x, gy):
          gx = gy[0] * 2.0 * x[0]
          return utils.force_array(gx, dtype=x[0].dtype),
  
  
  def square(x):
      """Elementwise square function.
  
      .. math::
         y_i = x_i ^ 2.
  
      Args:
          x (chainer.Variable or :class:`numpy.ndarray` or cupy.ndarray):
              Input variable.
  
      Returns:
          ~chainer.Variable: Output variable.
      """
      return Square()(x)
  
subject: Fix doc