code: def _create_variables(self, n_features, n_classes):
          
          self.W_ = tf.Variable(
              tf.zeros([n_features, n_classes]), name='weights')
          self.b_ = tf.Variable(
              tf.zeros([n_classes]), name='biases')
docs: Create the TensorFlow variables for the model.
  
          :param n_features: number of features
          :param n_classes: number of classes
          :return: self