@classmethod
    def _read_instruction_from_relative_instructions(cls, relative_instructions):
        """Returns ReadInstruction obj initialized with relative_instructions."""
        # Use __new__ to bypass __init__ used by public API and not conveniant here.
        result = cls.__new__(cls)
        result._init(relative_instructions)  # pylint: disable=protected-access
        return result

    def __init__(self, split_name, rounding=None, from_=None, to=None, unit=None):
        """Initialize ReadInstruction.