code: def execute(cls, ctx, op):
      in_data = ctx[op.inputs[0].key]
      out_chunk = op.outputs[0]
  
      if in_data is None:
          if op.output_types[0] == OutputType.dataframe:
              ctx[op.outputs[0].key] = build_empty_df(
                  out_chunk.dtypes,
                  index=out_chunk.index_value.to_pandas(),
              )
          else:
              ctx[op.outputs[0].key] = build_empty_series(
                  out_chunk.dtype,
                  name=out_chunk.name,
                  index=out_chunk.index_value.to_pandas(),
              )
          return
  
      if op.call_agg:
          result = in_data.agg(op.func, *op.args, **op.kwds)
      elif in_data.shape[0] > 0:
          # cannot perform groupby-transform over empty dataframe
          result = in_data.transform(op.func, *op.args, **op.kwds)
      else:
          if out_chunk.ndim == 2:
              result = pd.DataFrame(columns=out_chunk.dtypes.index)
          else:
              result = pd.Series(
                  [], name=out_chunk.name, dtype=out_chunk.dtype
              )
  
      if result.ndim == 2:
          if out_chunk.dtypes is not None:
              result = result.astype(out_chunk.dtypes, copy=False)
      else:
          if out_chunk.dtype is not None:
              result = result.astype(out_chunk.dtype, copy=False)
      ctx[op.outputs[0].key] = result
  
imports: import numpy
  import pandas
  from ...None import opcodes
  from ...core import OutputType
  from ...core.custom_log import redirect_custom_log
  from ...serialization.serializables import BoolField, TupleField, DictField, AnyField
  from ...utils import enter_current_session, quiet_stdio
  from ..operands import DataFrameOperandMixin, DataFrameOperand
  from ..utils import build_empty_df, build_empty_series, parse_index
label_desc: Use image node_id 9 for calling the GroupByTransform obj's underlying member method code with example usage: obj.execute(cls, ctx, op) without return types