一开始的语法错误

Question

我一直在遇到python和预期的缩进块的问题，它在while开头显示。任何帮助将不胜感激。该错误消息是一个SynthaxError，在while循环中的nah之后标记。

while choice!="nah":
    print("Please enter the room values in Meters")
    print()

    W=float(checked_input("Width:"))
    H=float(checked_input("Height: "))
    L=float(checked_input("Lenght: "))
    R=str(room_input("Room Name: "))
    f = open(R+".txt","w+")
    Area=Room_Area(H,L,W)
    Volume=Room_Volume(H,L,W)
    print()
    print ("Please type the number of your material option:")
    print()

    for i in Material_List:
        print (i)
    print()
    print("Option:")
    index=int(option_input(''))
    print()

    coeficientfactor= Coeficient_List[index-1]
    print("The Coeficient Factor of the material you chose is:",coeficientfactor)
    print("Your Room Volume is:",(Volume),"m3")
    print()
    print("Your RT60 is:", RT_60(Volume,Area,coeficientfactor),"Seconds")
    print()
    print()



    choice=input("Do you want to do another RT60? (yah or nah):")
    print()

print("Buh-bye!")