The following contains the JSON Schema for the Entities in the Collection representing the Knowledge Graph.
If validate is set to True, the schema is enforced upon insert and update.
See $jsonSchema <https://www.mongodb.com/docs/manual/reference/operator/query/jsonSchema/>_
The following defines the default entity_schema. It allows all possible values of "type" and "relationship".
If allowed_entity_types: List[str] is given to MongoDBGraphStore's constructor,
then self._schema["properties"]["type"]["enum"] = allowed_entity_types is added.
If allowed_relationship_types: List[str] is given to MongoDBGraphStore's constructor, additionalProperties is set to False, and relationship schema is provided for each key.
