trying python3-smbus for coding

#!/usr/bin/python3

from time import sleep
import smbus

bus = smbus.SMBus(1)
addr = 0x28
SENS_STS = 0x01
PRES_REF_H = 0x0B
PRES_REF_L = 0x0C
MEAS_RATE_H = 0x02
MEAS_RATE_L = 0x03
MEAS_CFG = 0x04

MEAS_STS = 0x07

CO2PPM_H = 0x05
CO2PPM_L = 0x06
sleep(1)

try:
    rack = int(input("Please type a 1 or 0, thank you... "))
    while True:
        if rack >= 1:
            bus.read_byte_data(addr, SENS_STS)
            bus.read_byte_data(addr, PRES_REF_H)
            bus.read_byte_data(addr, PRES_REF_L)
            bus.read_byte_data(addr, MEAS_RATE_H)
            bus.read_byte_data(addr, MEAS_RATE_L)
            bus.read_byte_data(addr, MEAS_CFG)
            bus.read_byte_data(addr, MEAS_STS)
            bus.read_byte_data(addr, CO2PPM_H)
            bus.read_byte_data(addr, CO2PPM_L)
            sleep(0.5)
            bus.write_byte_data(addr, PRES_REF_H, 0x03)
            bus.write_byte_data(addr, PRES_REF_L, 0xF5)
            bus.write_byte_data(addr, MEAS_RATE_H, 0x00)
            bus.write_byte_data(addr, MEAS_RATE_L, 0x0A)
            bus.write_byte_data(addr, MEAS_CFG, 0x01)
            OnePlus = str(CO2PPM_H) + str(CO2PPM_L)
            print("PPM of CO2 in your home is: ".format(OnePlus))
        elif rack == 0:
            bus.read_byte_data(addr, SENS_STS)
            bus.read_byte_data(addr, PRES_REF_H)
            bus.read_byte_data(addr, PRES_REF_L)
            bus.read_byte_data(addr, MEAS_RATE_H)
            bus.read_byte_data(addr, MEAS_RATE_L)
            bus.read_byte_data(addr, MEAS_CFG)
            bus.read_byte_data(addr, MEAS_STS)
            bus.read_byte_data(addr, CO2PPM_H)
            bus.read_byte_data(addr, CO2PPM_L)
            sleep(0.5)
            bus.write_byte_data(addr, PRES_REF_H, 0x03)
            bus.write_byte_data(addr, PRES_REF_L, 0xF5)
            bus.write_byte_data(addr, MEAS_RATE_H, 0x00)
            bus.write_byte_data(addr, MEAS_RATE_L, 0x0A)
            bus.write_byte_data(addr, MEAS_CFG, 0x01)
            TwoPlus = str(CO2PPM_H) + (str(CO2PPM_L)
            print("The PPM of CO2 in your home is: ".format(TwoPlus))
        else:
            pass
except KeyboardInterrupt:
    print("Done for now!")
    pass