class_docstr: Base class for all text based default handler.
  Contains various text based utility methods
class_docstr_tok: ["Base","class","for","all","text","based","default","handler",".","Contains","various","text","based","utility","methods"]
code: def get_source_vocab_path(self, ctx):
      properties = ctx.system_properties
      model_dir = properties.get("model_dir")
      source_vocab_path = os.path.join(model_dir, "source_vocab.pt")
  
      if os.path.isfile(source_vocab_path):
          return source_vocab_path
      else:
          raise Exception(
              "Missing the source_vocab file. Refer default handler "
              "documentation for details on using text_handler."
          )
  
imports: import logging
  import os
  import re
  import string
  import unicodedata
  from abc import ABC
  import torch
  import torch.nn.functional
  from captum.attr import LayerIntegratedGradients
  from torchtext.data.utils import get_tokenizer
  from ..utils.util import CLEANUP_REGEX
  from .base_handler import BaseHandler
  from .contractions import CONTRACTION_MAP
label_desc: Use image node_id 3 for calling the TextHandler obj's underlying member method code with example usage: obj.get_source_vocab_path(ctx) and returns: source_vocab_path