docstr: 将 tensor 的值设置为 value
docstr_tok: ["\u5c06","tensor","\u7684\u503c\u8bbe\u7f6e\u4e3a","value"]
code: def fill_value(self, tensor, value: float):
      """
      将 tensor 的值设置为 value
  
      """
      value = jittor.full_like(tensor, value)
      return value
  
file_path: fastNLP/fastNLP/core/metrics/backend/jittor_backend/backend.py
imports: import numpy
  from fastNLP.envs.imports import _NEED_IMPORT_JITTOR
  from fastNLP.core.metrics.backend import Backend
label_desc: Use image node_id 4 for calling the JittorBackend obj's underlying member method code with example usage: obj.fill_value(tensor, value) and returns: value