How to use the tts.describe_files_by_type function in TTS

def list_by_type(self,save_type):
    result=""
    for (name,id) in tts.describe_files_by_type(self.filesystem,save_type):
      result+="\n%s (%s)" % (name,id)
    return 0,result

def list_command(self):
    """ Populates the list box"""
    data=tts.describe_files_by_type(self.filesystem,self.save_type.get())
    self.file_list.delete(0,Tk.END)
    self.file_store={}
    i=0
    for (name,number) in data:
      self.file_list.insert(Tk.END,"%s (%s)" % (name,number))
      self.file_store[i]=number
      i+=1

def list_command(self):
    """ Populates the list box"""
    data=tts.describe_files_by_type(self.filesystem,self.save_type.get())
    self.file_list_box.config(state=Tk.NORMAL)
    self.file_list_box.delete(0,Tk.END)
    self.file_store={}
    i=0
    for (name,number) in data:
      self.file_list_box.insert(Tk.END,"%s (%s)\n" % (name,number))
      self.file_store[i]=number
      i+=1