code: def tile(cls, op: "HeadOptimizedDataSource"):
      if op.nrows is not None:
          return (yield from cls._tile_head(op))
      else:
          return cls._tile(op)
  
imports: import asyncio
  import uuid
  from typing import List, Optional, Union
  import numpy
  from ...core import recursive_tile
  from ...core.context import get_context, Context
  from ...config import options
  from ...oscar import ActorNotExist
  from ...serialization.serializables import Int64Field, StringField
  from ...typing import TileableType, OperandType
  from ...utils import parse_readable_size
  from ..core import IndexValue, OutputType
  from ..operands import DataFrameOperand, DataFrameOperandMixin
  from ..utils import merge_index_value
label_desc: Use image node_id 4 for calling the HeadOptimizedDataSource obj's underlying member method code with example usage: obj.tile(cls, op) and returns: unknown, cls