i2cdetect als Python3-Unterprogramm

#!/usr/bin/python3
import smbus # I2C

class I2C:
    def __init__(self):
         self.i2c = smbus.SMBus(1) # i2c bus: J8.3 (GPIO2) as SDA,
                                   #          J8.5 (GPIO3) as SCL
                                   
    def detect(self):
        # inspired by shell command "i2cdetect -y 1"
        print('     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f')
        for addr in range(0, 127, 16):
            lin = '{:02x}:'.format(addr)
            for i in range(0, 16):
                if addr + i < 3:
                    lin += '   '
                else:
                    try:
                        x = self.i2c.write_i2c_block_data(addr + i, 0, [])
                    except OSError:
                        lin += ' --'
                    else:
                        lin += ' {:02x}'.format(addr + i)
            print(lin)
                              
    def read(self, addr, reg, cnt):
        # returns a list of received data
        data = self.i2c.read_i2c_block_data(addr, reg, cnt)
        print('<RD addr {}, reg/ofs {} = {}'.format(hex(addr),
                                                    hex(reg),
                                                    data))
        return data
        
    def write(self, addr, reg, data):
        # no return value
        self.i2c.write_i2c_block_data(addr, reg, data)
        print('>WR addr {}, reg/ofs {}: {}'.format(
                  hex(addr),
                  hex(reg),
                  'set register' if data == [] else data))
        
# MAIN:
i2c = I2C()
i2c.detect()