text: import numpy as np
  
  class CrossEntropy(object):
      def __call__(self, y, T):
          return -(T * np.log(y) + (1 - T) * np.log(1 - y)).mean()
  
      def gradient(self, y, T):
          return (y - T) / (y * (1 - y)) / y.shape[0]
  