Nebula Service models.
To use, you should have the environment variable NEBULA_SERVICE_URL,
NEBULA_SERVICE_PATH and NEBULA_API_KEY set with your Nebula
Service, or pass it as a named parameter to the constructor.
Example:
.. code-block:: python
from langchain_community.llms import Nebula
nebula = Nebula( nebula_service_url="NEBULA_SERVICE_URL", nebula_service_path="NEBULA_SERVICE_PATH", nebula_api_key="NEBULA_API_KEY", )
