code: def _execute_combine(cls, ctx, op: "StatsModelsTrain"):
      # code from statsmodels.base.distributed_estimation::DistributedModel.fit
      results_list = [
          pickle.loads(ctx[inp.key]) for inp in op.inputs
      ]  # nosec
      params = op.join_method(results_list, **op.join_kwds)
      res_mod = op.model_class([0], [0], **op.init_kwds)
      result = op.results_class(res_mod, params, **op.results_kwds)
  
      ctx[op.outputs[0].key] = pickle.dumps(result)
  
imports: import pickle
  import cloudpickle
  from ....None import opcodes
  from ....core import OutputType, recursive_tile
  from ....core.context import get_context
  from ....core.operand import OperandStage, MergeDictOperand
  from ....serialization.serializables import KeyField, BytesField, DictField, Int32Field, Float32Field, FunctionField
  from ....utils import has_unknown_shape
label_desc: Use image node_id 20 for calling the StatsModelsTrain obj's underlying member method code with example usage: obj._execute_combine(cls, ctx, op) without return types