Infinite loop in own sorting function in python

I am very new to python, and as excersize I want to write sorting function just with my little knowledge of python. But my code ends in infinite loop, but I cant figure out why. Can anybody help?

here is my code

#create list
sezn = []
while True:
    try :
        a = int(input("Number: "))
        sezn.append(a)
    except :
        break
#print min, max and mean
print (sezn)
print("minimum: ", min(sezn))
print ("maximum: ", max(sezn))
fin = 0
for i in sezn:
    fin += i
mean = fin/len(sezn)
print ("mean: ", mean)
#sorting function    
sort = []
sez = []
index = 0
length = len(sezn)
print (length)
while index < length:
    for i in sezn:
        if i == min(sezn):
            sort.append(i)
        else:
            sez.append(i)
    index += 1
    sezn = sez
print(sort)