I've labbed the code and I'm getting the result it requests. what am I doing wrong?

# E.g. word_count("I do not like it Sam I Am") gets back a dictionary like:
# {'i': 2, 'do': 1, 'it': 1, 'sam': 1, 'like': 1, 'not': 1, 'am': 1}
# Lowercase the string to make it easier.
def word_count(string):
    #convert string into a list broken up by spaces " "
    string = string.lower()
    result = string.split(" ")
    #make empty dictionary
    my_dict = {}
    #make key for counting
    key = 0
    #make check_list
    check_list = []
    #for each word in list see how many times it occurs and add 1 to key
    for word in result:
        #check check_list for word
        if word in check_list:
            continue
        else:
            key = result.count(word)
            my_dict.update({word: key})
            check_list.append(word)

    return my_dict