def _use_inf_as_null(key):
 from pandas.core.config import get_option
 flag = get_option(key)
 if flag:
  globals()['_isnull'] = _isnull_old
 else:
  globals()['_isnull'] = _isnull_new

def _use_inf_as_null ( key ) : from pandas . core . config import get_option flag = get_option ( key ) if flag : globals ( ) [ '_isnull' ] = _isnull_old else : globals ( ) [ '_isnull' ] = _isnull_new
option change callback for null/inf behaviour choose which replacement for numpy .