code: async def fromURL(
              cls, url, *, credentials=None, insecure=False):
          
          try:
              description = await helpers.fetch_api_description(
                  url, insecure=insecure)
          except helpers.RemoteError as error:
              # For now just re-raise as SessionError.
              raise SessionError(str(error))
          else:
              session = cls(description, credentials)
              session.insecure = insecure
              return session
docs: Return a `SessionAPI` for a given MAAS instance.