Python 3.9 is now generally available.

google.appengine.api.datastore_types.ToPropertyPb

Creates type-specific entity_pb2.PropertyValues.

Determines the type and meaning of the PropertyValue based on the Python type of the input value(s).

NOTE: This function does not validate anything!

name String or unicode; the property name.
values The values for this property, either a single one or a list of them. All values must be a supported type. Lists of values must all be of the same type.

A list of entity_pb2.Property instances.