Obscure python syntax error

Been writing python for a long time. When I wrote this code, I could not figure out why I was getting a syntax error.

d1 = dict(
display_name='Matt Wilson',)

d2 = dict(
email_address='[email protected]',

It is the trailing comma after **d1. It is not OK. Which is really weird, because the trailing comma after display_name=’Matt Wilson’ is just fine.