Error during accessing contact using Python Sl4a

Question

I'm executing this code to get contacts using Sl4A Library:

import sl4a
droid=sl4a.Android()
m=droid.contactsGet(['display_name','primary_phone'])
for contact in m:
    print(m[0],"\t",m[1])
    print("\n")

The above code is producing

java.lang.NullPointerException Result(id=1, result =None, error ='Javalang.NullPointerException')