code: def __init__(self):
      sigmoid = Sigmoid()
      self.log_func = sigmoid
      self.log_grad = sigmoid.gradient
  
file_path: ML-From-Scratch/mlfromscratch/supervised_learning/xgboost.py
imports: from __future__ import division, print_function
  import numpy
  import progressbar
  from mlfromscratch.utils import train_test_split, standardize, to_categorical, normalize
  from mlfromscratch.utils import mean_squared_error, accuracy_score
  from mlfromscratch.supervised_learning import XGBoostRegressionTree
  from mlfromscratch.deep_learning.activation_functions import Sigmoid
  from mlfromscratch.utils.misc import bar_widgets
  from mlfromscratch.utils import Plot
label_desc: Use image node_id 1 to create a new LogisticLoss object  with example: obj = LogisticLoss()