code: def __call__(self, a):
      kws = [
          {"shape": (np.nan,), "order": TensorOrder.C_ORDER, "_idx_": i}
          for i in range(a.ndim)
      ]
      return ExecutableTuple(
          self.new_tensors([a], kws=kws, output_limit=len(kws))
      )
  
file_path: mars/mars/tensor/indexing/nonzero.py
imports: import numpy
  from ...None import opcodes
  from ...core import ExecutableTuple, recursive_tile
  from ...serialization.serializables import KeyField
  from ..operands import TensorHasInput, TensorOperandMixin
  from ..datasource import tensor
  from ..core import TensorOrder
  from .unravel_index import unravel_index
label_desc: Use image node_id 2 for calling the TensorNonzero obj's underlying member method code with example usage: obj.__call__(a) and returns: ExecutableTuple