DocumentAdmin: 'StringField' object has no attribute 'document_type' about django-mongoadmin HOT 10 CLOSED

            if hasattr(f, 'field') and f.field:
                embedded_document = f.field.document_type
            elif hasattr(f, 'document_type'):
                embedded_document = f.document_type
            else:
                continue

{'_data': {'motherID': None, 'families': [], 'tags': [], 'personal': None, 'fatherID': None, 'childrenIDs': [], 'missing': None, 'api_id': None, 'events': None, 'note': None, 'cached': False, 'api': None, 'relation': None, 'user': None, 'spouseID': None, 'synced': datetime.datetime(2012, 2, 15, 11, 47, 49, 316099), 'parents': [], 'ordinances': None, 'id': None}, '_initialised': True}

class Person(Document):
    user = ReferenceField('User',required=True)
    # valid api values are "nfs"
    api = StringField(max_length=50,required=True)
    api_id = StringField(max_length=10,required=True)
    cached = BooleanField(default=False)
    synced = DateTimeField(default=datetime.datetime.now)
    personal = EmbeddedDocumentField(Personal)
    events = EmbeddedDocumentField(Events)
    ordinances = EmbeddedDocumentField(Ordinances)
    families = ListField(EmbeddedDocumentField(Family))
    parents = ListField(EmbeddedDocumentField(Parents))
    missing = EmbeddedDocumentField(Missing)
    relation = StringField()
    motherID = StringField(max_length=10)
    fatherID = StringField(max_length=10)
    # spouse and children should eventually be kept as part of a family
    spouseID = StringField(max_length=10)
    childrenIDs = ListField()
    tags = ListField()
    note = StringField()

'NoneType' object has no attribute 'document_type'
{'admin_site': <mongoadmin.sites.AdminSite object at 0x2770c50>, 'model': <class 'family.models.Person'>, 'document': <class 'family.models.Person'>, 'inline_instances': [<mongoadmin.options.EmbeddedStackedDocumentAdmin object at 0x2e945d0>], 'opts': <mongodbforms.documentoptions.DocumentMetaWrapper object at 0x2e944d0>}

'NoneType' object has no attribute 'document_type'
{'admin_site': <mongoadmin.sites.AdminSite object at 0x2770c50>, 'model': <class 'family.models.Person'>, 'document': <class 'family.models.Person'>, 'inline_instances': [<mongoadmin.options.EmbeddedStackedDocumentAdmin object at 0x2e945d0>, <mongoadmin.options.EmbeddedStackedDocumentAdmin object at 0x2e947d0>], 'opts': <mongodbforms.documentoptions.DocumentMetaWrapper object at 0x2e944d0>}