code: def dt_s_tup_to_string(dt_s_tup):
      """
  
      Parameters
      ----------
      dt_s_tup : tuple
          A tuple of length 2.
          The first entry is a string specifying the deterministic term without
          any information about seasonal terms (for example "nc" or "c").
          The second entry is an int specifying the number of seasons.
  
      Returns
      -------
      dt_string : str
          Returns dt_s_tup[0], if dt_s_tup[1] is 0 (i.e. no seasons).
          If dt_s_tup[1] is > 0 (i.e. there are seasons) add an "s" to the string
          in dt_s_tup[0] like in the following examples:
          "nc" --> "ncs"
          "c" --> "cs"
          "ct" --> "cst"
      """
      dt_string = dt_s_tup[
          0
      ]  # string for identifying the file to parse.
      if dt_s_tup[1] > 0:  # if there are seasons in the model
          if dt_string == "nc":
              dt_string = dt_string[:2] + "s"
          if dt_string == "c" or dt_string == "ct":
              dt_string = dt_string[:1] + "s" + dt_string[1:]
      return dt_string
  
imports: import os
  import re
  import numpy
  from .parse_jmulti_vecm_output import stringify_var_names, sublists
label_desc: Use image node_id 2 for calling a global function with example usage: dt_s_tup_to_string(dt_s_tup) and returns: dt_string