LPTHW Exercise 48, my lexicon.py version

lexicon.py

def scan(sentence):
    direction = ('north', 'south', 'east', 'west', 'down', 'up', 'left', 'right', 'back')
    verb = ('go', 'stop', 'kill', 'eat')
    stop = ('the', 'in', 'of', 'from', 'at', 'it')
    noun = ('door', 'bear', 'princess', 'cabinet')
    # create a tuple named 'number' which consists of integers from 0 till 100000
    number = tuple(range(0, 100001, 1))
    # convers the tuple elements into strings
    number = tuple(map(str, number))
    error = ('ASDFADFASDF', 'IAS')

    sentence = sentence.split()
    new_list = []

    for i in sentence:
        if i in noun:
            i = [('noun', i)]
            new_list += i

        elif i in error:
            i = [('error', i)]
            new_list += i

        elif i in direction:
            i = [('direction', i)]
            new_list += i

        elif i in verb:
            i = [('verb', i)]
            new_list += i

        elif i in stop:
            i = [('stop', i)]
            new_list += i

        elif i in number:
            try:
                i = int(i)
                i = [('number', i)]
                new_list += i
            except ValueError:
                return None              

    return new_list