code: def fillna_method(request):
      """
      Parametrized fixture giving method parameters 'ffill' and 'bfill' for
      Series.fillna(method=<method>) testing.
      """
      return request.param
  
imports: import operator
  import pytest
  from pandas._config.config import _get_option
  from pandas import Series, options
label_desc: Use image node_id 17 for calling a global function with example usage: fillna_method(request) and returns: request