Ask mongongine not to use _cls in queries

class BaseEvent(Document):
	type = IntField(required=True)
	source_id = IntField(required=True)

	meta = {
        'allow_inheritance': True,
        'collection': 'event',
    }


class SimpleEvent(BaseEvent):
    start_time = DateTimeField(required=True)
    end_time = DateTimeField(required=True)
	
	meta = {
        'allow_inheritance': True,
        'collection': 'event',
    }

# event type = 1
class EventA(BaseEvent):
 	pass


# event type = 2
class EventB(SimpleEvent):
 	x = IntField(required=True)
 	# ........................

I have many types of events, all events are saved in collection 'event'.
I want to define documents:

• Use inheritance for define event class (for control fields which each event has)
• Use field type for querying event of a type
• Ask mongongine not to use _cls in all queries ?

No files or tests are named. Start by reproducing the inheritance example and tracing how MongoEngine builds queries for the shared event collection; define completion as supporting the requested type-based querying without relying on _cls, while preserving the documented inheritance behavior.