pack布局错误，left没定义

问题遇到的现象和发生背景

tkinter pack布局提示 NameError: name 'LEFT' is not defined

问题相关代码，请勿粘贴截图

import tkinter
from tkinter import Frame

def btnHelloClicked():
cd=float(entrycd.get())
label2.config(text="%.2f°C=%.2f°F"%(cd,cd*1.8+32))

window=tkinter.Tk()
window.title("森林质量精准评价体系1.0")
window.geometry("500x500")

label1=tkinter.Label(window,text='请输入各项评价因子数值及权重',fg='black',)
label1.pack()

label3=tkinter.Label(window,text='生产力',fg='black',)
label3.pack()

fm1=Frame(window)
entrycd=tkinter.Entry(fm1,text='0').pack(side=LEFT)
entrycd=tkinter.Entry(fm1,text='0').pack(side=LEFT)
fm1.pack()

运行结果及报错内容

Traceback (most recent call last):
File "C:\Users\Administrator\Desktop\asfsa.py", line 19, in
entrycd=tkinter.Entry(fm1,text='0').pack(LEFT)
NameError: name 'LEFT' is not defined

这样：pack( side=’left’)