def parse(cls, fptr, offset, length):
        """Parse Label box.

        Parameters
        ----------
        fptr : file
            Open file object.
        offset : int
            Start position of box in bytes.
        length : int
            Length of the box in bytes.

        Returns
        -------
        LabelBox
            Instance of the current label box.
        """
        num_bytes = offset + length - fptr.tell()
        read_buffer = fptr.read(num_bytes)
        label = read_buffer.decode('utf-8')
        return cls(label, length=length, offset=offset)
Parse Label box.

        Parameters
        ----------
        fptr : file
            Open file object.
        offset : int
            Start position of box in bytes.
        length : int
            Length of the box in bytes.

        Returns
        -------
        LabelBox
            Instance of the current label box.