def get(self, ii, default=None, msg_if_none=None):
        """
        Get an item from Container - a wrapper around
        Container.__getitem__() with defaults and custom error message.

        Parameters
        ----------
        ii : int or str
            The index or name of the item.
        default : any, optional
            The default value returned in case the item `ii` does not exist.
        msg_if_none : str, optional
            If not None, and if `default` is None and the item `ii` does
            not exist, raise ValueError with this message.
        """
        try:
            out = self[ii]

        except (IndexError, ValueError):
            if default is not None:
                out = default

            else:
                if msg_if_none is not None:
                    raise ValueError(msg_if_none)

                else:
                    raise

        return out