docstr: Registers a new backend by importing the corresponding module
      and adding the correspond `Backend` class in Backend._LOADED_BACKEND
      under the key `backend_name`
  
  Parameters
  ----------
  backend_name : str, name of the backend to load
  
  Raises
  ------
  ValueError
      If `backend_name` does not correspond to one listed
          in `_KNOWN_BACKEND`
docstr_tok: ["Registers","a","new","backend","by","importing","the","corresponding","module","and","adding","the","correspond","`","Backend","`","class","in","Backend._LOADED_BACKEND","under","the","key","`","backend_name","`","Parameters","--","--","--","--","--","backend_name",":","str",",","name","of","the","backend","to","load","Raises","--","--","--","ValueError","If","`","backend_name","`","does","not","correspond","to","one","listed","in","`","_KNOWN_BACKEND","`"]
code: def load_backend(cls, backend_name):
      """Registers a new backend by importing the corresponding module
          and adding the correspond `Backend` class in Backend._LOADED_BACKEND
          under the key `backend_name`
  
      Parameters
      ----------
      backend_name : str, name of the backend to load
  
      Raises
      ------
      ValueError
          If `backend_name` does not correspond to one listed
              in `_KNOWN_BACKEND`
      """
      if backend_name not in cls.available_backend_names:
          msg = f"Unknown backend name {backend_name!r}, known backends are {cls.available_backend_names}"
          raise ValueError(msg)
      if backend_name not in Backend._available_backends:
          importlib.import_module(
              f"tensorly.backend.{backend_name}_backend"
          )
      if backend_name in Backend._available_backends:
          backend = Backend._available_backends[backend_name]()
          # backend = getattr(module, )()
          cls._loaded_backends[backend_name] = backend
  
      return backend
  
imports: import warnings
  from .core import Backend, backend_array
  import importlib
  import os
  import threading
  from contextlib import contextmanager
  import inspect
  import types
  import sys
label_desc: Use image node_id 9 for calling the BackendManager obj's underlying member method code with example usage: obj.load_backend(cls, backend_name) and returns: backend