docstr: Prepare text lablel by given Lexicon_Table.
docstr_tok: ["Prepare","text","lablel","by","given","Lexicon_Table","."]
code: def prepare_text_label(self, label_str, Lexicon_Table):
      """
      Prepare text lablel by given Lexicon_Table.
      """
      if len(Lexicon_Table) == 36:
          return label_str.lower()
      else:
          return label_str
  
imports: import math
  import cv2
  import numpy
  from skimage.morphology._skeletonize import thin
  from ppocr.utils.e2e_utils.extract_textpoint_fast import sort_and_expand_with_direction_v2
label_desc: Use image node_id 16 for calling the PGProcessTrain obj's underlying member method code with example usage: obj.prepare_text_label(label_str, Lexicon_Table) and returns: label_str, label_str