code: def _use_inf_as_na(key):
      """Option change callback for na/inf behaviour
      Choose which replacement for numpy.isnan / -numpy.isfinite is used.
  
      Parameters
      ----------
      flag: bool
          True means treat None, NaN, INF, -INF as null (old way),
          False means None and NaN are null, but INF, -INF are not null
          (new way).
  
      Notes
      -----
      This approach to setting global module values is discussed and
      approved here:
  
      * http://stackoverflow.com/questions/4859217/
        programmatically-creating-variables-in-python/4859312#4859312
      """
      from pandas.core.config import get_option
  
      flag = get_option(key)
      if flag:
          globals()["_isna"] = _isna_old
      else:
          globals()["_isna"] = _isna_new
  
file_path: catboost/contrib/python/pandas/py2/pandas/core/dtypes/missing.py
imports: import numpy
  from pandas._libs import lib, missing
  from pandas._libs.tslibs import NaT, iNaT
  from .common import _NS_DTYPE, _TD_DTYPE, ensure_object, is_bool_dtype, is_complex_dtype, is_datetime64_dtype, is_datetime64tz_dtype, is_datetimelike, is_datetimelike_v_numeric, is_dtype_equal, is_extension_array_dtype, is_float_dtype, is_integer_dtype, is_object_dtype, is_period_dtype, is_scalar, is_string_dtype, is_string_like_dtype, is_timedelta64_dtype, needs_i8_conversion, pandas_dtype
  from .generic import ABCDatetimeArray, ABCExtensionArray, ABCGeneric, ABCIndexClass, ABCMultiIndex, ABCSeries, ABCTimedeltaArray
  from .inference import is_list_like
label_desc: Use image node_id 4 for calling a global function with example usage: _use_inf_as_na(key) without return types