code: def test_foreign_session_factory_dummy():
      sesh = Session.from_foreign_session(None)
      assert isinstance(sesh, DummySession)
  
imports: from unittest import mock
  import pytest
  from fiona.session import DummySession, AWSSession, Session, OSSSession, GSSession, SwiftSession, AzureSession
label_desc: Use image node_id 17 for calling a global function with example usage: test_foreign_session_factory_dummy() without return types