code: def _call_series_series(self, lhs: TileableType, rhs: TileableType):
      idx = self._merge_index(
          lhs.index_value, rhs.index_value, how=self.join
      )
      kws = [
          {"index_value": idx, "shape": (np.nan,), "dtype": lhs.dtype},
          {"index_value": idx, "shape": (np.nan,), "dtype": rhs.dtype},
      ]
      return self.new_tileables([lhs, rhs], kws=kws)
  
imports: from typing import Any, Optional, Union
  import numpy
  from ...None import opcodes
  from ...core import get_output_types, recursive_tile, OutputType
  from ...serialization.serializables import AnyField, KeyField, StringField, Int16Field, Int64Field
  from ...typing import TileableType
  from ..operands import DataFrameOperand, DataFrameOperandMixin
  from ..align import align_dataframe_dataframe, align_dataframe_series, align_series_series
  from ..core import IndexValue
  from ..utils import validate_axis, parse_index, build_empty_df
label_desc: Use image node_id 6 for calling the DataFrameAlign obj's underlying member method code with example usage: obj._call_series_series(lhs, rhs) and returns: self