code: def _multiply_low_high(self, a, b):
      low = a * b
      high = int(a) * int(b)
      high = np.array(
          high >> (np.dtype(self._dtype).itemsize * 8),
          dtype=self._dtype,
      )
      return low, high
  
imports: import numpy
  import pytest
  import scipy.stats
  import torch
  import triton
  import triton.language
label_desc: Use image node_id 4 for calling the CustomPhilox4x obj's underlying member method code with example usage: obj._multiply_low_high(a, b) and returns: low,  high