Scrollbar in Tkinter not moveable

I'm in the beginning stages of building a program where I can take items from a TreeView and move them into a listbox. I have added scrollbars to both the Treeview and listbox so that as they get longer, I can scroll to see the contents. Currently, I have populated the Treeview with more items than can fit in the window. I have the ability to scroll the Treeview with the mouse wheel, but when I click and drag the box on the scrollbar, the scrollbar will not move. I'm using Python 3.7. I could use some help figuring out what's going on.

import tkinter as tk
from tkinter import ttk
import l5x



root = tk.Tk()
root.geometry("600x400")
root.resizable(False, False)
root.title("TreeView Example")

tree_frame = ttk.Frame(root)
list_frame = ttk.Frame(root)
tree = ttk.Treeview(tree_frame)
tree_scroll = ttk.Scrollbar(tree_frame,orient="vertical",command=tree.yview())
tree.configure(yscrollcommand=tree_scroll.set)
listbox = tk.Listbox(tree_frame)
list_scroll = ttk.Scrollbar(tree_frame,orient="vertical",command=listbox.yview())
listbox.configure(yscrollcommand=list_scroll.set)


tree_frame.columnconfigure(0, weight=1)
tree_frame.columnconfigure(1, weight=1)
tree_frame.columnconfigure(2, weight=1)
tree_frame.columnconfigure(3, weight=1)


for i in range(0,20):
    tree.insert('','end',i,text="blah")

tree_frame.grid(row=0,column=0,sticky="NSEW")
tree.grid(row=0,column=0,sticky="NSEW")
tree_scroll.grid(row=0,column=1,sticky="NS")
listbox.grid(row=0,column=2,sticky="NSEW")
list_scroll.grid(row=0,column=3,sticky="NS")



root.mainloop()

The command attribute requires you pass a reference to a callable function. Instead, you're calling the yview() method and giving the results to the command attribute.

Your scrollbar definition needs to look like this:

tree_scroll = ttk.Scrollbar(tree_frame,orient="vertical",command=tree.yview)
list_scroll = ttk.Scrollbar(tree_frame,orient="vertical",command=listbox.yview)