entry.fields appears to drop information

[Nico Schlömer]

I have a bibtex entry that gives

>>> print(entry)
Entry(u'article', fields=FieldDict([(u'title', u'Krylov subspace methods')]), persons=OrderedCaseInsensitiveDict([(u'author', [Person(u'Liesen'), Person(u'Strako\u0161')])]))

>>> print(entry.fields)
FieldDict([(u'title', u'Krylov subspace methods')])

What happened to persons in entry.fields?

[Nico Schlömer]

Ah, I see now: persons is no member of fields.