class_docstr: 执行评测时使用的 backend，是所有 backend 的父类。Backend 及其子类的所有方法都必须是无状态的。
class_docstr_tok: ["\u6267\u884c\u8bc4\u6d4b\u65f6\u4f7f\u7528\u7684","backend\uff0c\u662f\u6240\u6709","backend","\u7684\u7236\u7c7b\u3002Backend","\u53ca\u5176\u5b50\u7c7b\u7684\u6240\u6709\u65b9\u6cd5\u90fd\u5fc5\u987b\u662f\u65e0\u72b6\u6001\u7684\u3002"]
docstr: 将 tensor 的值设置为 ``value``
  
  :param tensor: 传进来的张量
  :param value: 需要填充的值
docstr_tok: ["\u5c06","tensor","\u7684\u503c\u8bbe\u7f6e\u4e3a","``","value","``",":","param","tensor",":","\u4f20\u8fdb\u6765\u7684\u5f20\u91cf",":","param","value",":","\u9700\u8981\u586b\u5145\u7684\u503c"]
code: def fill_value(self, tensor, value: float):
      """
      将 tensor 的值设置为 ``value``
  
      :param tensor: 传进来的张量
      :param value: 需要填充的值
      """
      return value
  
file_path: fastNLP/fastNLP/core/metrics/backend/backend.py
imports: from ..utils import AggregateMethodError
label_desc: Use image node_id 4 for calling the Backend obj's underlying member method code with example usage: obj.fill_value(tensor, value) and returns: value