def __init__(self, header, hlen=None, hdata=None):
        self.header = header
        self.hlen = hlen
        self.hdata = hdata
:param :class:`~oppy.cell.fixedlen.FixedLenCell.Header` header:
dataset/ETHPy150Open nskinkel/oppy/oppy/cell/fixedlen.py/Created2Cell.__init__