def __contains__(self, uid: str) -> bool:
        """
        Checks whether a container with a given ID exists.

        Parameter:
            uid:    the ID of the container.

        Returns:
            True if the container exists; false if not.
        """
        try:
            self[uid]
            return True
        except KeyError:
            return False
def __contains__ ( self , uid : str ) -> bool : try : self [ uid ] return True except KeyError : return False
Checks whether a container with a given ID exists.

        Parameter:
            uid:    the ID of the container.

        Returns:
            True if the container exists; false if not.