def __init__(self, format, readers, idoffsets):
        
        self.format = format
        self.readers = readers
        self.offsets = idoffsets
        self.current = 0
        self._prep()
:param format: the :class:`~whoosh.formats.Format` object for the field
dataset/ETHPy150Open dokipen/whoosh/src/whoosh/postings.py/MultiPostingReader.__init__