Python - Encryption program - i don't get why it throws these errors : i am creating an encryption program, in python, with a simple cipher, reverse the string and go 3 letters forward in the alphabet.

However i am getting these errors and i don't understand why i get them:

<pre>original = input('Enter a phrase: ')
actual_word = original[::-1]

def mid(s, offset, amount):
    return s[offset:offset+amount]

def encrypt(word):
    for i in len(word):
        newtxt = mid(word, i, 1)
        newtxt = chr(ord(newtxt)+3)
        coded = coded + newtxt
    return coded

encrypted = encrypt(original)
print(encrypted)
input('Press ENTER to exit')

'''
IT THROWS THIS ERROR
Traceback (most recent call last):
  File "C:\Users\MHT\Desktop\Python\Kryptering\Encryption.py", line 14, in <module>
    encrypted = encrypt(original)
  File "C:\Users\MHT\Desktop\Python\Kryptering\Encryption.py", line 8, in encrypt
    for i in len(word):
TypeError: 'int' object is not iterable
'''
</pre>