docs: def suggest_filename(file_path, exists=None):
      """
      Try if exist path and append number to its end.
      For debug you can set as input if file exists or not.
      """
      import os.path
      import re
      if not isinstance(exists, bool):
          exists = os.path.exists(file_path)
  
      if exists:
          file_path, file_extension = os.path.splitext(file_path)
          # print(file_path)
          m = re.search(r"_\d+$", file_path)
          if m is None:
              # cislo = 2
              new_cislo_str = "_2"
          else:
              cislostr = (m.group())
              cislo = int(cislostr[1:]) + 1
              # it is normal number
              file_path = file_path[:-len(cislostr)]
              new_cislo_str = "_" + str(cislo)
  
          file_path = file_path + new_cislo_str + file_extension  # .zfill(2)
          # trorcha rekurze
          file_path = suggest_filename(file_path)
  
      return file_path