class_docstr: fastNLP中各种Embedding的基类
class_docstr_tok: ["fastNLP\u4e2d\u5404\u79cdEmbedding\u7684\u57fa\u7c7b"]
docstr: 这个值可能会大于实际的embedding矩阵的大小。
  :return:
docstr_tok: ["\u8fd9\u4e2a\u503c\u53ef\u80fd\u4f1a\u5927\u4e8e\u5b9e\u9645\u7684embedding\u77e9\u9635\u7684\u5927\u5c0f\u3002",":","return",":"]
code: def num_embeddings(self) -> int:
      r"""
      这个值可能会大于实际的embedding矩阵的大小。
      :return:
      """
      return len(self._word_vocab)
  
imports: from abc import abstractmethod
  from typing import Union, Tuple
  from ...envs.imports import _NEED_IMPORT_TORCH
  import numpy
  from .utils import get_embeddings
label_desc: Use image node_id 9 for calling the TokenEmbedding obj's underlying member method code with example usage: obj.num_embeddings() and returns: len