class_docstr: CER and WER
docstr: get character error rate
code: def getCER(self):
      "get character error rate"
      return self.edChars / self.numChars
  
file_path: calamari/calamari_ocr/thirdparty/ctcwordbeamsearch/Metrics.py
imports: from __future__ import division
  from __future__ import print_function
  import re
  import editdistance
label_desc: Use image node_id 4 for calling the Metrics obj's underlying member method code with example usage: obj.getCER() and returns: unknown