Tkinter按钮样式不起作用，错误：找不到布局样式按钮

Question

我正在尝试设置按钮的样式，以使其在单击时变色。这给我一个错误，即找不到我存储了样式的变量stylebutton。如何正确分配此变量？

这是用于较大的Tkinter GUI。

    stylebutton = ttk.Style()
    stylebutton.map("stylebutton",
        foreground=[('pressed', 'red'), ('active', 'blue')],
        background=[('pressed', '!disabled', 'black'), ('active''white'))
        button = ttk.Button(self, text="Login as a student", style = 
       "stylebutton",command=lambda: controller.show_frame(PageOne))

我希望按钮会更改颜色，但是程序无法运行并给出错误代码：

  

回溯（最近通话最近）：

File "C:/Users/LENOVO/PycharmProjects/CSinternal/LearnIt.py", line 1263, in <module>
app = LearnIt()
File "C:/Users/LENOVO/PycharmProjects/CSinternal/LearnIt.py", line 73, in __init__
frame = F(container, self,)
File "C:/Users/LENOVO/PycharmProjects/CSinternal/LearnIt.py", line 122, in __init__
command=lambda: controller.show_frame(PageOneS))
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python36-32\lib\tkinter\ttk.py", line 614, in __init__
Widget.__init__(self, master, "ttk::button", kw)
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python36-32\lib\tkinter\ttk.py", line 559, in __init__
tkinter.Widget.__init__(self, master, widgetname, kw=kw)
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python36-32\lib\tkinter\__init__.py", line 2293, in __init__
(widgetName, self._w) + extra + self._options(cnf))
_tkinter.TclError: Layout stylebutton not found