Linear search sample

#First, we declare the function:
def linear(a_list, an_item):

    #Then, we iterate through the list:
    for i in range(len(a_list)):

        #If we've found the item, we're done! Go ahead and return this index.
        if a_list[i] == an_item:
            return i

    #If we reach the end of the function it means we never returned an index, which means we never found the item and can return False.
    return False

a_list = [5, 1, 3, 6, 7, 3, 1, 6, 7, 8, 3, 6]
print(linear(a_list, 6))