Error when a trigger is created

Hello,

I'm trying to create a trigger, but is returning a bad request.

Here it is my code

from pydocumentdb import document_client

DB_DATABASE = 'test_database2'
DB_COLLECTION = 'my_collection'
client = document_client.DocumentClient(
    'https://localhost:3000/', {'masterKey': ''})

print("deleting database")
try:
    db = next((data for data in client.ReadDatabases(
    ) if data['id'] == DB_DATABASE))
    client.DeleteDatabase(db['_self'])
except:
 pass

print("creating database")
db = client.CreateDatabase({'id': DB_DATABASE})

print("creating collection")
collection = client.CreateCollection(db['_self'], {'id': DB_COLLECTION})

path = 'dbs/{}/colls/{}'.format(DB_DATABASE, DB_COLLECTION)

# Create trigger
trigger_definition = {
    'id': '_type',
    'serverScript': """
        // Ensures that documents have a _type field.
        function validateNameExists() {
            var collection = getContext().getCollection();
            var request = getContext().getRequest();
            var docToCreate = request.getBody();

            // Reject documents that do not have a name property by throwing an exception.
            if (!docToCreate._type) {
                throw new Error('Document must include a "_type" property.');
            }
        }
    """,
    'triggerType': 'Pre',
    'triggerOperation': 'All'
}
try:
    client.CreateTrigger(collection['_self'], trigger_definition)
except Exception as e:
    print(e)

The request is created for 'https://localhost:3000//dbs/wgLLAG--C30lC30lC30lD0--/colls/V2u_QG--C30lC30lC30lC0--/triggers/'

With this header

<class 'dict'>: {'Cache-Control': 'no-cache', 'x-ms-version': '2016-07-11', 'User-Agent': 'Windows/10 Python/3.6.8 documentdb-python-sdk/2.0.0', 'x-ms-consistency-level': 'Session', 'x-ms-session-token': '', 'Content-Type': 'application/json', 'Accept': 'application/json'}

And with this body

<class 'dict'>: {'id': '_type', 'triggerType': 'Pre', 'triggerOperation': 'All', 'body': '\n        // Ensures that documents have a _type field.\n        function validateNameExists() {\n            var collection = getContext().getCollection();\n            var request = getContext().getRequest();\n            var docToCreate = request.getBody();\n\n            // Reject documents that do not have a name property by throwing an exception.\n            if (!docToCreate._type) {\n                throw new Error(\'Document must include a "_type" property.\');\n            }\n        }\n    '}```

Unfortunately, trigger is not supported yet.