code: def execute(cls, ctx, op: "StatsModelsTrain"):
      if op.merge:  # pragma: no cover
          super().execute(ctx, op)
      elif op.stage == OperandStage.combine:
          cls._execute_combine(ctx, op)
      else:
          cls._execute_map(ctx, op)
  
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 21 for calling the StatsModelsTrain obj's underlying member method code with example usage: obj.execute(cls, ctx, op) without return types