code: def fill_binop(left, right, fill_value):
      """
      If a non-None fill_value is given, replace null entries in left and right
      with this value, but only in positions where _one_ of left/right is null,
      not both.
  
      Parameters
      ----------
      left : array-like
      right : array-like
      fill_value : object
  
      Returns
      -------
      left : array-like
      right : array-like
  
      Notes
      -----
      Makes copies if fill_value is not None and NAs are present.
      """
      if fill_value is not None:
          left_mask = isna(left)
          right_mask = isna(right)
  
          # one but not both
          mask = left_mask ^ right_mask
  
          if left_mask.any():
              # Avoid making a copy if we can
              left = left.copy()
              left[left_mask & mask] = fill_value
  
          if right_mask.any():
              # Avoid making a copy if we can
              right = right.copy()
              right[right_mask & mask] = fill_value
  
      return left, right
  
imports: from __future__ import annotations
  import operator
  from typing import TYPE_CHECKING, cast
  import numpy
  from pandas._libs.ops_dispatch import maybe_dispatch_ufunc_to_dunder_op
  from pandas._typing import Axis, AxisInt, Level
  from pandas.util._decorators import Appender
  from pandas.core.dtypes.common import is_array_like, is_list_like
  from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
  from pandas.core.dtypes.missing import isna
  from pandas.core import algorithms, roperator
  from pandas.core.ops.array_ops import arithmetic_op, comp_method_OBJECT_ARRAY, comparison_op, get_array_op, logical_op, maybe_prepare_scalar_for_op
  from pandas.core.ops.common import get_op_result_name, unpack_zerodim_and_defer
  from pandas.core.ops.docstrings import _flex_comp_doc_FRAME, _op_descriptions, make_flex_doc
  from pandas.core.ops.invalid import invalid_comparison
  from pandas.core.ops.mask_ops import kleene_and, kleene_or, kleene_xor
  from pandas.core.ops.methods import add_flex_arithmetic_methods
  from pandas.core.roperator import radd, rand_, rdiv, rdivmod, rfloordiv, rmod, rmul, ror_, rpow, rsub, rtruediv, rxor
label_desc: Use image node_id 1 for calling a global function with example usage: fill_binop(left, right, fill_value) and returns: left,  right