Wont drive P10 to P17； about micropython-pcf8575

[weirros]

import pcf8575
from machine import I2C, Pin

i2c = I2C(scl=Pin(13), sda=Pin(12))
pcf = pcf8575.PCF8575(i2c)

def read8575():
  k1=pcf.port
  k2= str(bin(k1))
  k3 = []
  for i in range(len(k2[2:])):
    i=i+1
    #print(i,k2[-i])
    k3.append(int(k2[-i]))
  
  for j in range(16-len(k2[2:])):
    k3.append(0)
  
  return k3
  
f1=read8575()
print (f1)

for reading all pins

exec(open('8575.py').read(),globals())
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

[mcauser]

Are you using a pcf8575 breakout, or the chip directly?
Are you sure you have a pcf8575 and not a pcf8574?
Do you have pull ups on your I2C line?