hex - decimal converter

hexdecimal.py

def hextodecimal(A):
    sayi=0
    A=A[::-1]
    for i in range(len(A)):
        if A[i]=="A":
            sayi=sayi+(10*(16**i))
        elif A[i]=="B":
            sayi=sayi+(11*(16**i))
        elif A[i]=="C":
            sayi=sayi+(12*(16**i))
        elif A[i]=="D":
            sayi=sayi+(13*(16**i))
        elif A[i]=="E":
            sayi=sayi+(14*(16**i))
        elif A[i]=="F":
            sayi=sayi+(15*(16**i))
        else:
            sayi=sayi+(int(A[i])*(16**i))
    return sayi

def binarytodecimal(A):
    kalan=0
    yenidizi=[]
    son=""
    while A>16:
        kalan=A%16
        if kalan==15:
            yenidizi.append("F")
        elif kalan==14:
            yenidizi.append("E")
        elif kalan==13:
            yenidizi.append("D")
        elif kalan==12:
            yenidizi.append("C")
        elif kalan==11:
            yenidizi.append("B")
        elif kalan==10:
            yenidizi.append("A")
        else:
            yenidizi.append(kalan)
        A=int(A/16)
    if A==15:
        yenidizi.append("F")
    elif A==14:
        yenidizi.append("E")
    elif A==13:
        yenidizi.append("D")
    elif kalan==12:
        yenidizi.append("C")
    elif kalan==11:
        yenidizi.append("B")
    elif kalan==10:
        yenidizi.append("A")
    else:
        yenidizi.append(A)
    for i in yenidizi:
        son=son+str(i)
    son=son[::-1]
    return son

print (hextodecimal("1234"))

print (binarytodecimal(4660))