code: def tile(cls, op: "GroupByIndex"):
      in_groupby = op.inputs[0]
      out_groupby = op.outputs[0]
  
      chunks = []
      for c in in_groupby.chunks:
          if op.output_types[0] == OutputType.series_groupby:
              params = dict(
                  shape=(c.shape[0],),
                  name=op.selection,
                  index=(c.index[0],),
                  dtype=c.dtypes[op.selection],
                  index_value=c.index_value,
                  key_dtypes=c.key_dtypes,
              )
          else:
              params = c.params.copy()
              params["dtypes"] = out_groupby.dtypes
              params["selection"] = op.selection
              params["shape"] = (c.shape[0], len(op.selection))
              params["columns_value"] = out_groupby.columns_value
  
          new_op = op.copy().reset_key()
          chunks.append(new_op.new_chunk([c], **params))
  
      new_op = op.copy().reset_key()
      params = out_groupby.params.copy()
      new_nsplits = (
          (in_groupby.nsplits[0], (len(op.selection),))
          if out_groupby.ndim == 2
          else (in_groupby.nsplits[0],)
      )
      params.update(dict(chunks=chunks, nsplits=new_nsplits))
      return new_op.new_tileables([in_groupby], **params)
  
file_path: mars/mars/dataframe/groupby/getitem.py
imports: from collections.abc import Iterable
  from ...None import opcodes
  from ...core import OutputType
  from ...serialization.serializables import AnyField
  from ..operands import DataFrameOperandMixin, DataFrameOperand
  from ..utils import parse_index
label_desc: Use image node_id 6 for calling the GroupByIndex obj's underlying member method code with example usage: obj.tile(cls, op) and returns: new_op