class_docstr: Base class for all the templates.
  Most of methods are abstract, with some exceptions to hold the common methods for all template, such as ``loss_ids``, ``save``, ``load``.
  
  Args:
      tokenizer (:obj:`PreTrainedTokenizer`): A tokenizer to appoint the vocabulary and the tokenization strategy.
      placeholder_mapping (:obj:`dict`): A place holder to represent the original input text.
class_docstr_tok: ["Base","class","for","all","the","templates",".","Most","of","methods","are","abstract",",","with","some","exceptions","to","hold","the","common","methods","for","all","template",",","such","as","``","loss_ids","``",",","``","save","``",",","``","load","``",".","Args",":","tokenizer","(",":","obj",":","`","PreTrainedTokenizer","`",")",":","A","tokenizer","to","appoint","the","vocabulary","and","the","tokenization","strategy",".","placeholder_mapping","(",":","obj",":","`","dict","`",")",":","A","place","holder","to","represent","the","original","input","text","."]
docstr: A hook to do something when template text was set.
  The designer of the template should explicitly know what should be done when the template text is set.
code: def on_text_set(self):
      r"""
      A hook to do something when template text was set.
      The designer of the template should explicitly know what should be done when the template text is set.
      """
      raise NotImplementedError
  
imports: from abc import abstractmethod
  import json
  from transformers.file_utils import ModelOutput
  from openprompt.config import convert_cfg_to_dict
  from transformers.utils.dummy_pt_objects import PreTrainedModel
  from openprompt.utils.utils import signature
  from yacs.config import CfgNode
  from openprompt.data_utils import InputFeatures, InputExample
  import torch
  import torch.nn
  from typing import *
  from transformers.tokenization_utils import PreTrainedTokenizer
  from openprompt.utils.logging import logger
  import numpy
  import torch.nn.functional
label_desc: Use image node_id 15 for calling the Template obj's underlying member method code with example usage: obj.on_text_set() without return types