code: def sigmoid(z):
      return 1 / (1 + _np.exp(-z))
  
file_path: turicreate/src/python/turicreate/toolkits/object_detector/_detection.py
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import numpy
label_desc: Use image node_id 4 for calling a global function with example usage: sigmoid(z) and returns: unknown