def METHOD_NAME(self, db: Session, system: System) -> None:
    """Add a user as one of the system managers for the given system
    If applicable, also update the systems on the user's client
    """
    if (
        not type(system).__name__ == "System"
    ):  # Checking type instead of with isinstance to avoid import errors
        raise SystemManagerException(
            "Must pass in a system to set user as system manager."
        )
    if self in system.data_stewards:
        raise SystemManagerException(
            f"User '{self.username}' is already a system manager of '{system.name}'."
        )
    self.systems.append(system)
    self.save(db=db)
    if self.client:
        self.client.update(db=db, data={"systems": self.system_ids})