def METHOD_NAME(self, matrix_name: str) -> MatrixRecord:
    """Returns a model Matrix Record for manipulation in memory"""
    if matrix_name.lower() not in self.__items:
        raise Exception("There is no matrix record with that name")
    if not self.__items[matrix_name.lower()]._exists:
        raise Exception("This matrix was deleted during this session")
    return self.__items[matrix_name.lower()]