code: def exponential_kernel(alpha=1.0, tol=1e-9):
      def kernel(distance):
          kernel_value = np.exp(-alpha * np.abs(distance))
          if kernel_value > tol:
              return kernel_value
          else:
              return 0.0
  
      return kernel
  
file_path: gluonts/src/gluonts/time_feature/holiday.py
imports: from typing import Callable, List
  import numpy
  import pandas
  from pandas.tseries.holiday import SU, TH, EasterMonday, GoodFriday, Holiday, USColumbusDay, USLaborDay, USMartinLutherKingJr, USMemorialDay, USPresidentsDay, USThanksgivingDay
  from pandas.tseries.offsets import DateOffset, Day, Easter
label_desc: Use image node_id 3 for calling a global function with example usage: exponential_kernel(alpha, tol) and returns: kernel, kernel_value, int