将tkinter导入为tk ImportError：没有名为tkinter的模块

Question

File "employee_gui.py", line 8, in <module>
import tkinter as tk
ImportError: No module named tkinter

我尝试运行文件，但显示此错误。

import tkinter as tk
from tkinter import messagebox
import tkinter.ttk as ttk # for combobox

请帮助