class_docstr: class representing nodes in a prefix tree
code: def __init__(self):
      self.children = (
          {}
      )  # all child elements beginning with current prefix
      self.isWord = False
  
file_path: calamari/calamari_ocr/thirdparty/ctcwordbeamsearch/PrefixTree.py
imports: from __future__ import division
  from __future__ import print_function
label_desc: Use image node_id 1 to create a new Node object  with example: obj = Node()