code: def cutoff_filename(prefix, suffix, input_str):
      
      if prefix is not '':
          if input_str.startswith(prefix):
              input_str = input_str[len(prefix):]
      if suffix is not '':
          if input_str.endswith(suffix):
              input_str = input_str[:-len(suffix)]
      return input_str
docs: Cuts off the start and end of a string, as specified by 2 parameters
  
      Parameters
      ----------
      prefix : string, if input_str starts with prefix, will cut off prefix
      suffix : string, if input_str end with suffix, will cut off suffix
      input_str : the string to be processed
  
      Returns
      -------
      A string, from which the start and end have been cut