Display the endpoint in the Custom AI portal
The SDK has been recently updated, and now the TrainingApi(trainingkey) class has been replaced by the CustomVisionTrainingClient(trainingkey, endpoint=endpoint) class.
The only way to find the endpoint in the portal is to create a project.
That doesn't help if you want to create the project programmatically using the SDK. Here's the code you would need to write:
from azure.cognitiveservices.vision.customvision.training import CustomVisionTrainingClient
trainer = CustomVisionTrainingClient(TRAINING_KEY, endpoint=ENDPOINT)
Create a new project
print ("Creating project...")
project = trainer.create_project("My Project")
However, I can't determine the ENDPOINT unless I've already created the project using the UI.
At present, the Custom Vision preview only appears to be available in the South Central US region, so it's a safe bet that the endpoint is the one you showed above; but that's not really a particularly satisfying solution - I'd expect the endpoint (or at least the region) to be reflected in the customvision.ai portal (or in the Properties page of the resource in the Azure portal if using this in an Azure subscription).