code: def _is_uint64(self, x):
      return not isinstance(x, int) and x.dtype == "uint64"
  
imports: import unittest
  import numpy
  from cupy import testing
  from cupy_tests.core_tests.fusion_tests import fusion_utils
label_desc: Use image node_id 1 for calling the TestFusionArrayBitwiseOperator obj's underlying member method code with example usage: obj._is_uint64(x) and returns: unknown