code: def key_func_builder(x, na_position):
      if x is None:
          if na_position == "first":
              return -1e8
          else:
              return 1e8
      else:
          return x
  
imports: import functools
  import operator
  import numpy
  import pandas
  import pyarrow
  import pytest
  import cudf
  from cudf import NA
  from cudf._lib.copying import get_element
  from cudf.api.types import is_scalar
  from cudf.testing._utils import DATETIME_TYPES, NUMERIC_TYPES, TIMEDELTA_TYPES, assert_eq
label_desc: Use image node_id 14 for calling a global function with example usage: key_func_builder(x, na_position) and returns: x, unknown, int