python – assigning result of a function call, where the function has no return

contexto: ‘Haciendo una calculadora con interfaz en Python con las bibliotecas Tkinter y math’

Abajo de cada botón que le asigne a la interfaz me sale el error en la ventana PROBLEMS “assigning result of a function call, where the function has no return.” independientemente de que en cada botón me de error, aun así funciona pero no entiendo el porque del error.

introducir la descripción de la imagen aquí

from tkinter import *
from math import *

ventana = Tk()
ventana.title ("Casio SuperPower 3000")
ventana.geometry("400x600")
ventana.resizable(False,False)
ventana.configure(background="gray42")


color_boton="gray99"
ancho_boton=10
alto_boton=3

operacion = ""
texto_pantalla = StringVar()
def clear():
    global operacion
    operacion = ""
    texto_pantalla.set("0")
def click(b):
    global operacion
    operacion += str(b)
    texto_pantalla.set(operacion)
def resultado():
    global operacion
    try:
        r = str(eval(operacion))
    except:
        r = "error404"
    texto_pantalla.set(r)

clear()

Boton0 = Button(ventana, text="0",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(0)) .grid(row=1,column=0,pady=10)
Boton1 = Button(ventana, text="1",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(1)) .grid(row=1,column=1,pady=10)
Boton2 = Button(ventana, text="2",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(2)) .grid(row=1,column=2,pady=10)
Boton3 = Button(ventana, text="3",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(3)) .grid(row=1,column=3,pady=10)

#segunda fila
Boton4 = Button(ventana, text="4",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(4)) .grid(row=2,column=0,pady=10)
Boton5 = Button(ventana, text="5",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(5)) .grid(row=2,column=1,pady=10)
Boton6 = Button(ventana, text="6",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(6)) .grid(row=2,column=2,pady=10)
Boton7 = Button(ventana, text="7",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(7)) .grid(row=2,column=3,pady=10)

#tercera fila
Boton8 = Button(ventana, text="8",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(8)) .grid(row=3,column=0,pady=10)
Boton9 = Button(ventana, text="9",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(9)) .grid(row=3,column=1,pady=10)
BotomPi= Button(ventana, text="π" ,bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("pi")) .grid(row=3,column=2,pady=10)
BotonPunto = Button(ventana, text=".",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(".")) .grid(row=3,column=3,pady=10)

#cuarta fila
BotonSuma = Button(ventana, text="+",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("+")) .grid(row=4,column=0,pady=10)
BotonResta = Button(ventana, text="-",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("-")) .grid(row=4,column=1,pady=10)
BotonMult = Button(ventana, text="*",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("*")) .grid(row=4,column=2,pady=10)
BotonDiv = Button(ventana, text="/",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("/")) .grid(row=4,column=3,pady=10)

#quinta fila
BotonRaiz = Button(ventana, text="√",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(sqrt)) .grid(row=5,column=0,pady=10)
BotonClear = Button(ventana, text="C",bg=color_boton,width=ancho_boton,height=alto_boton,command=clear) .grid(row=5,column=1,pady=10)
BotonEXP = Button(ventana, text="exp",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(exp)) .grid(row=5,column=2,pady=10)
BotonIgual = Button(ventana, text="=",bg=color_boton,width=ancho_boton,height=alto_boton,command=resultado) .grid(row=5,column=3,pady=10)

#sexta FILA
BotonParenIz = Button(ventana, text="(",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("(")) .grid(row=6,column=0,pady=10)
BotonParenDer = Button(ventana, text=")",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click(")")) .grid(row=6,column=1,pady=10)
BotonPorc = Button(ventana, text="%",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("%")) .grid(row=6,column=2,pady=10)
BotonLog = Button(ventana, text="Log",bg=color_boton,width=ancho_boton,height=alto_boton,command=lambda:click("log")) .grid(row=6,column=3,pady=10)

pantalla = Entry(ventana, font=("arial", 20, "bold") ,width=22,borderwidth=10,background="deep sky blue", textvariable=texto_pantalla)
pantalla.grid(row=0,column=0,columnspan=4,padx=20,pady=20)

ventana.mainloop()