Problem with the suntax


I am on the first part of the "Student becomes Teacher". But even the first line is showing the error saying it is invalid syntax. I am new to Python programming. So i am not able to find an error. Please help me.
lloyd = {"name": "Lloyd","homework":,"quizzes":,"tests":}
alice = {"name": "Alice","homework":,"quizzes":,"tests":}
tyler = {"name":"Tyler","homework":,"quizzes":,"tests":}


Here the comma is i the wrong place n all of your dictionaries and remove the colon after tests in all of them as well,