class _RelativeInstruction:
    """Represents a single parsed slicing instruction, can use % and negatives."""

    splitname: str
    from_: Optional[int] = None  # int (starting index) or None if no lower boundary.
    to: Optional[int] = None  # int (ending index) or None if no upper boundary.
    unit: Optional[str] = None
    rounding: Optional[str] = None