In [1]: p = People.by_username('mmcgrath')

In [2]: p.emails
Out[2]: {'bugzilla': <fas.model.PersonEmails object at 0xa599c0c>}

In [3]: p.emails['bugzilla'].purpose = 'primary'

In [4]: session.refresh(p)

In [5]: p.emails
Out[5]: {'primary': <fas.model.PersonEmails object at 0xa599c0c>}

In [6]: e = PersonEmails(email='mmcgrath@fedoraproject.org', purpose = 'bugzilla')

In [7]: e.person = p

In [8]: session.flush()

In [9]: p.emails
Out[9]: 
{'bugzilla': <fas.model.PersonEmails object at 0xa53706c>,
 'primary': <fas.model.PersonEmails object at 0xa599c0c>}