Asterisk ARI doubt in basic wiki program

Plz help me with this basic doubt.

Regarding ARI example given in asterisk wiki page (

To print json returned by StasisStart event
print channel.json.get(‘caller’) will print ------> {u’name’: u’’, u’number’: u’666666’}

how to print the caller.number value; (here it is 666666)

I got the solution

print channel.json[‘caller’][‘number’]