More Python Homework Help

#a function to spell out numbers in words
def spellnum(num,join=True):
    #Lists of number words

        thousands = ['','thousand','million']
        tens = ['','ten','twenty','thirty','forty','fifty','sixty','seventy', \
            'eighty','ninety']
        teens = ['','eleven','twelve','thirteen','fourteen','fifteen','sixteen', \
             'seventeen','eighteen','nineteen']
        units = ['','one','two','three','four','five','six','seven','eight','nine'] 
        #Empty List for number words
    words = [] 
        #zero case
        if num==0: words.append('zero')
        #how to handle negative numbers
    if num < 0: words.append('negative') 
        num = abs(num)
        #a series of steps to process the numbers and turn them into words
    numStr = '%d'%num
        numStrLen = len(numStr)
        groups = (numStrLen+2)/3
        numStr = numStr.zfill(groups*3)
        for i in range(0,groups*3,3):
            h,t,u = int(numStr[i]),int(numStr[i+1]),int(numStr[i+2])
            g = groups-(i/3+1)
            if h>=1:
                words.append(units[h])
                words.append('hundred')
            if t>1:
                words.append(tens[t])
                if u>=1: words.append(units[u])
            elif t==1:
                if u>=1: words.append(teens[u])
                else: words.append(tens[t])
            else:
                if u>=1: words.append(units[u])
            if (g>=1) and ((h+t+u)>0): words.append(thousands[g]+',')
        #final joining of parts
    if join: return ' '.join(words)
        return words

#sample calls            
print spellnum(0)                    
print spellnum(10)
print spellnum(120000)
print spellnum(-90902)

#Recording of Run
%run C:/Users/Nancy/Desktop/SelfStudyMaterials/draftassign4.py
zero
ten
one hundred twenty thousand,
negative ninety thousand, nine hundred two
End
#drnanjo author
#with generous help from: Mr.Regna, Prof. Haight, Stack Overflow and Treehouse