code: def get_dates_delta(start_date, end_date, time_delta):
      """return knot index based on date difference normalized with the number of steps by frequency provided
  
      Parameters
      ----
      start_date : numpy datetime
      end_date : numpy datetime array
      time_delta : time delta between dates
      """
      date_diff = end_date - start_date
      # can also be deemed as the "knot_idx"
      norm_delta = np.round(date_diff / time_delta).astype(int)
  
      return norm_delta
  
imports: import numpy
  import pandas
  from ..exceptions import IllegalArgument
label_desc: Use image node_id 2 for calling a global function with example usage: get_dates_delta(start_date, end_date, time_delta) and returns: norm_delta