class_docstr: Logsigmoid Loss
  -\log(rac{1}{1 + \exp(-l_i \cdot f(t_i))})
  l_i : label i from {-1, 1}
  f : score
  t_i : triple i
code: def __call__(self, score, label):
      pass
  
label_desc: Use image node_id 2 for calling the BaseLogsigmoidLoss obj's underlying member method code with example usage: obj.__call__(score, label) without return types