code: def cu_time_execution(cb, enable=False) -> Optional[float]:
      return (
          time_execution_cuda_style(
              cb,
              cuda.CUevent,
              cuda.cuEventCreate,
              cuda.cuEventRecord,
              cuda.cuEventSynchronize,
              cuda.cuEventDestroy_v2,
              cuda.cuEventElapsedTime,
              enable=enable,
          )
          if not CUDACPU
          else cpu_time_execution(cb, enable=enable)
      )
  
imports: from __future__ import annotations
  import subprocess, hashlib, tempfile, ctypes, ctypes.util, functools, re
  from pathlib import Path
  from typing import Tuple, Optional
  import gpuctypes.cuda
  from tinygrad.helpers import DEBUG, getenv, from_mv, init_c_var, colored, cpu_time_execution, compile_cuda_style, encode_args_cuda_style, time_execution_cuda_style
  from tinygrad.device import Compiled, LRUAllocator, MallocAllocator
  from tinygrad.codegen.kernel import LinearizerOptions
  from tinygrad.renderer.cstyle import CUDARenderer
label_desc: Use image node_id 3 for calling a global function with example usage: cu_time_execution(cb, enable) and returns: unknown