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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def parse(cls, fptr, offset, length):
 """Parse number list 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 number list box. """

        num_bytes = offset + length - fptr.tell()
        raw_data = fptr.read(num_bytes)
        num_associations = int(len(raw_data) / 4)
        lst = struct.unpack('>' + 'I' * num_associations, raw_data)
        return cls(lst, length=length, offset=offset)