Trying to Calculating CRC-16 in Python

I am starting to do a new big project so I started to learn about CRC(Cyclic redundancy check). After I had learned about it, I made one (CRC-16, with polynomial x^16+x^15+x^2+1, that equal to hex 0x8005), But when I checked if I did it fine, I found out it right but not the answer I wanted to get. I am using the website: http://crccalc.com/ In the code, I entered the binary value: 0100010101010011 (equal to 0x4553) and got the result is 1001111111101100 ( equal to 0x9FEC) I found out on the website is the right result but it not what I expected to get(I thought I'd get 0xAD72).

I have two questions:

1. How do I change my code to support CRC-16/ARC and not CRC-16/BUYPASS?

2. Why the polynomial x^16+x^15+x^2+1 equal to 0x8005 and not 0xC005? Thanks a lot!

my python code:

    def stXor(a,b):
    if(a==b):
        return "0"
    else:
        return "1"

def stshl(str1,shift):
    temp=""
    temp=str1
    for i in range(shift):
        temp=temp[1:]
    return temp

def get_error(data,padding=True):
    good=data
    lst=["0","0","0","0","0","0","0","0","0","0","0","0","0","0","0","0"]
    if(padding):
        good=data+"0"*16
    now="0"

    while len(good)>0:

        now=lst[0]
        lst[0]= stXor(lst[1],now) #x^15
        lst[1]=lst[2]
        lst[2]=lst[3]
        lst[3]=lst[4]
        lst[4]=lst[5]
        lst[5]=lst[6]
        lst[6]=lst[7]
        lst[7]=lst[8]
        lst[8]=lst[9]
        lst[9]=lst[10]
        lst[10]=lst[11]
        lst[11]=lst[12]
        lst[12]=lst[13]
        lst[13]=stXor(lst[14],now)# x^2
        lst[14]=lst[15]
        lst[15]=stXor(good[0],now)
        good=stshl(good,1)


    a=""
    for letter in lst:
        a+=letter


    return a


data="0100010101010011"

print("data entered: "+"\nhex: "+str(hex(int(data, 2)))+"\nBinary: "+data)


a=get_error(data)
print("Result: "+"\nhex: "+str(hex(int(a, 2)))+"\nBinary: "+a)

printed output:

data entered:

hex: 0x4553

Binary: 0100010101010011

Result:

hex: 0x9fec

Binary: 1001111111101100