can someone please help whats wrong with below code ?

t = int(input()) for i in range(t): n = str(input()) thousands = ["", "Thousand", "Million", "Billion", "Trillion"] units = ["", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"] teens = ["Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"] tens = ["", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"]

lisn = []
for i in range(len(n), 0, -3):
    lisn += [n[i - 3:i]]
if len(n) % 3 != 0:
    lisn[len(n) // 3] = n[:len(n) - (len(n) // 3) * 3]

for i in range(len(lisn)):
    lisn[i] = str(int(lisn[i]))
for i in range(len(lisn)):
    if len(lisn[i]) == 1:
        lisn[i] = units[int(lisn[i])]
    elif len(lisn[i]) == 2:
        if int(lisn[i]) < 20:
            lisn[i] = teens[int(lisn[i][1])]
        else:
            if int(lisn[i][1]) == 0:
                lisn[i] = tens[int(lisn[i])] + ' ' + 'Zero'
            elif int(lisn[i][1]) != 0:
                lisn[i] = tens[int(lisn[i][0])] + ' ' + units[int(lisn[i][1])]
    elif len(lisn[i]) == 3:
        if lisn[i][1] == '0':
            if lisn[i][2] == '0':
                lisn[i] = units[int(lisn[i][0])] + ' ' + 'Hundred'
            elif lisn[i][2] != '0':
                lisn[i] = units[int(lisn[i][0])] + ' ' + 'Hundred' + ' ' + units[int(lisn[i][2])]
        else:
            lis = units[int(lisn[i][0])] + ' ' + 'Hundred' + ' '
            str_ = int(lisn[i][1:])
            if str_ < 10:
                lis += units[str_]
            if 10 <= str_ < 20:
                lis += teens[int(str(str_)[1])]
            elif str_ > 20 and lisn[i][2] == 0:
                lis += tens[str_]
            elif str_ > 20 and lisn[i][2] != 0:
                lis += tens[int(str(str_)[0])] + ' ' + units[int(str(str_)[1])]
            lisn[i] = lis
for i in range(len(lisn)):
    if lisn[i] != '':
        lisn[i] += " " + thousands[i]
lisn.reverse()
i = 0
while i < len(lisn):
    if lisn[i] == '':
        lisn.remove(lisn[i])
        i += -1
    i += 1
if len(lisn) == 0:
    print('Zero')
else:
    print(*lisn)