Codewars kata, error

python

#1

from random import randint
def alphabet_position(text):
        text =  list(text)
        for item in text:
       
            randomnumber=randint(0,len(text))
            if item.isalpha():
                text.remove(item)
            if item == "1":
                text.remove(item)
            print str(randomnumber)

i entered the codewars site and this is one of its exercises and this is my solution but it says an error

this is the required:
Welcome. In this kata you are required to, given a string, replace every letter with its position in the alphabet. If anything in the text isn't a letter, ignore it and don't return it. a being 1, b being 2, etc. As an example:

alphabet_position("The sunset sets at twelve o' clock.")
Should return "20 8 5 19 21 14 19 5 20 19 5 20 19 1 20 20 23 5 12 22 5 15 3 12 15 3 11" (As a string.)
and this is the link:
here
and this is the error i have given:
Tests for each letter:
1
✘ None should equal '1'
i think i did not do anything wrong if you answer me fast then i thank you for this