code: def execute_one_chunk(cls, ctx, op):
      a = ctx[op.inputs[0].key]
      (inp,), device_id, xp = as_same_device(
          [a], device=op.device, ret_extra=True
      )
      with device(device_id):
          ctx[op.outputs[0].key] = xp.count_nonzero(inp, axis=op.axis)
  
file_path: mars/mars/tensor/reduction/count_nonzero.py
imports: import numpy
  from ...None import opcodes
  from ..array_utils import device, as_same_device
  from .sum import TensorSum
  from .core import TensorReduction, TensorReductionMixin
label_desc: Use image node_id 4 for calling the TensorCountNonzero obj's underlying member method code with example usage: obj.execute_one_chunk(cls, ctx, op) without return types