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`
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 TenalgBackend._available_tenalg_backends:
          importlib.import_module(
              f"tensorly.tenalg.{backend_name}_tenalg"
          )
      if backend_name in TenalgBackend._available_tenalg_backends:
          backend = TenalgBackend._available_tenalg_backends[
              backend_name
          ]()
          # backend = getattr(module, )()
          cls._loaded_backends[backend_name] = backend
  
      return backend
  
file_path: tensorly/tensorly/tenalg/__init__.py
imports: import sys
  import importlib
  import threading
  from ..backend import BackendManager, dynamically_dispatched_class_attribute
  from .base_tenalg import TenalgBackend
  from .svd import SVD_FUNS, svd_interface, truncated_svd
label_desc: Use image node_id 2 for calling the TenalgBackendManager obj's underlying member method code with example usage: obj.load_backend(cls, backend_name) and returns: backend