Caesar Cypher--- I don't understand why it doesn't work

[ironsheep]

alphabet= "abcdefghijklmnopqrstuvwxyz"
cleartext= input()
cleartext=cleartext_lowercase()
def encrypt(cleartext):
    codedtext = " "
    for character in cleartext:
            if character in alphabet:
                newcharacter= (alphabet.find(character) + 13) %26
                codedtext += alphabet[newcharacter]
            elif:
                codedtext += character
            return codedtext
print(encrypt(cleartext))

This is my python code for a caesar cipher I made after watching the Youtube Channel KidsCanCode Lesson 1.10. I already asked Chris Bradfield for help and thanks to his input, I fixed the errors he told me, but I still have errors. I don't want to bug him by asking him again to look at why this code doesn't work. My goal is to type in sheep and have the secret message as furrc. I recommend that you watch Chris Bradfield's video for clarification.

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Just run the program by typing in the word sheep-- and you will get syntax error( even though elif: is cif correct), why does python not accept elif. My goal is to cesear cipher the word sheep.

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How are you writing with/in a green bar??

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Also, why does it say Unladen Swallow under my username???