count on ListField of EmbeddedDocumentField fails

[DavidBord]

    class B(EmbeddedDocument):
        c = StringField()

    class A(Document):
        b = ListField(EmbeddedDocumentField(B))

    A.objects(b=[{'c': 'c'}]).count()

    class B(EmbeddedDocument):
        c = StringField()

Traceback (most recent call last):
    A.objects(b=[{'c': 'c'}]).count()
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/queryset.py", line 104, in count
    return super(QuerySet, self).count(with_limit_and_skip)
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/base.py", line 347, in count
    return self._cursor.count(with_limit_and_skip=with_limit_and_skip)
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/base.py", line 1481, in _cursor
    self._cursor_obj = self._collection.find(self._query,
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/base.py", line 1515, in _query
    self._mongo_query = self._query_obj.to_query(self._document)
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/visitor.py", line 90, in to_query
    query = query.accept(QueryCompilerVisitor(document))
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/visitor.py", line 155, in accept
    return visitor.visit_query(self)
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/visitor.py", line 78, in visit_query
    return transform.query(self.document, **query.query)
  File "/Users/db/Documents/mongoengine/mongoengine/queryset/transform.py", line 95, in query
    value = field.prepare_query_value(op, value)
  File "/Users/db/Documents/mongoengine/mongoengine/fields.py", line 705, in prepare_query_value
    return self.field.prepare_query_value(op, value)
  File "/Users/db/Documents/mongoengine/mongoengine/fields.py", line 570, in prepare_query_value
    value = self.document_type._from_son(value)
  File "/Users/db/Documents/mongoengine/mongoengine/base/document.py", line 686, in _from_son
    class_name = son.get('_cls', cls._class_name)
AttributeError: 'list' object has no attribute 'get'