class_docstr: generic GPU backend must be subclassed by a specific backend before being used 
code: def backend_init(self):
      super().backend_init()
  
      from ipyexperiments.utils.pynvml_gate import load_pynvml_env
  
      self.pynvml = load_pynvml_env()
  
imports: import gc
  import logging
  import os
  import psutil
  import sys
  import threading
  import time
  import weakref
  from IPython import get_ipython
  from IPython.core.magics.namespace import NamespaceMagics
  from collections import namedtuple
  from .cell_logger import CellLogger, b2mb, int2width, get_nvml_gpu_id
label_desc: Use image node_id 2 for calling the IPyExperimentsGPU obj's underlying member method code with example usage: obj.backend_init() without return types