**I'm brand new to Tkinter, and am building a tiny UI for interaction with a ML program. Here's the code I'm using for the UI window I've created:**

```py
from tkinter import *
from tkinter import ttk

class UI:

    def __init__(self, root):

        root.title("Retirement Savings Estimator")

        mainframe = ttk.Frame(root, padding="3 3 12 12")
        mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
        root.columnconfigure(0, weight=1)
        root.rowconfigure(0, weight=1)

        self.age = IntVar()
        self.age = ttk.Entry(mainframe, width=7, textvariable=self.age)
        self.age.grid(column=2, row=1, sticky=(W, E))
        ttk.Label(mainframe, text ="Enter your age: ").grid(column=1, row=1, sticky=(W, E))

        self.yearly_salary = StringVar()
        self.yearly_salary = ttk.Entry(mainframe, width=7, textvariable=self.yearly_salary)
        self.yearly_salary.grid(column=2, row=2, sticky=(W, E))
        ttk.Label(mainframe, text="Enter your gross yearly wages: ").grid(column=1, row=2, sticky=(W, E))

        for child in mainframe.winfo_children():
            child.grid_configure(padx=5, pady=5)

        ttk.Label(mainframe, text="Press the Calculate button to get your estimate: ").grid(column=1, row=3, sticky=(W, E))
        action = ttk.Button(mainframe, text="Calculate", default = "active", command = UI).grid(column=2, row=3, sticky=(W, E))
        self.age.focus()
        root.bind('<Return>', action)

    def predict_savings(*args, root):
        try:  
            user_age = int(self.age.get())
            yr_salary = float(self.yearly_salary.get())
            estimate = regr.predict(user_age, yr_salary)
            ttk.Label(mainframe, text="Your Estimated Amount to Save For Retirement: " + estimate).grid(column=1, row=4, sticky=(W, E))
        except ValueError:
            pass

root = Tk()   
UI(root)
root.mainloop()

```

**Here's the error message I'm getting when pressing the 'Calculate' button in the UI window:**

```
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\jesst\anaconda3\lib\tkinter\__init__.py", line 1892, in __call__
    return self.func(*args)
TypeError: __init__() missing 1 required positional argument: 'root'

```

I've tried adding 'root' to the predict\_savings() function to see if this fixes the issue, and a different error generates. I'm not sure what else to try. Any ideas would be excellent.