How to use the virtualenv.fileview function in virtualenv

def do_file(file, offset=0, size=maxint):
        file = fileview(file, offset, size)
        # Read magic number
        magic = read_data(file, BIG_ENDIAN)
        if magic == FAT_MAGIC:
            # Fat binaries contain nfat_arch Mach-O binaries
            nfat_arch = read_data(file, BIG_ENDIAN)
            for n in range(nfat_arch):
                # Read arch header
                cputype, cpusubtype, offset, size, align = read_data(file, BIG_ENDIAN, 5)
                do_file(file, offset, size)
        elif magic == MH_MAGIC:
            do_macho(file, 32, BIG_ENDIAN)
        elif magic == MH_CIGAM:
            do_macho(file, 32, LITTLE_ENDIAN)
        elif magic == MH_MAGIC_64:
            do_macho(file, 64, BIG_ENDIAN)
        elif magic == MH_CIGAM_64:

def __init__(self, fileobj, start=0, size=maxint):
        if isinstance(fileobj, fileview):
            self._fileobj = fileobj._fileobj
        else:
            self._fileobj = fileobj
        self._start = start
        self._end = start + size
        self._pos = 0

def do_file(file, offset=0, size=maxint):
        file = fileview(file, offset, size)
        # Read magic number
        magic = read_data(file, BIG_ENDIAN)
        if magic == FAT_MAGIC:
            # Fat binaries contain nfat_arch Mach-O binaries
            nfat_arch = read_data(file, BIG_ENDIAN)
            for _ in range(nfat_arch):
                # Read arch header
                cputype, cpusubtype, offset, size, align = read_data(file, BIG_ENDIAN, 5)
                do_file(file, offset, size)
        elif magic == MH_MAGIC:
            do_macho(file, 32, BIG_ENDIAN)
        elif magic == MH_CIGAM:
            do_macho(file, 32, LITTLE_ENDIAN)
        elif magic == MH_MAGIC_64:
            do_macho(file, 64, BIG_ENDIAN)
        elif magic == MH_CIGAM_64:

def do_file(file, offset=0, size=maxint):
        file = fileview(file, offset, size)
        # Read magic number
        magic = read_data(file, BIG_ENDIAN)
        if magic == FAT_MAGIC:
            # Fat binaries contain nfat_arch Mach-O binaries
            nfat_arch = read_data(file, BIG_ENDIAN)
            for n in range(nfat_arch):
                # Read arch header
                cputype, cpusubtype, offset, size, align = read_data(file, BIG_ENDIAN, 5)
                do_file(file, offset, size)
        elif magic == MH_MAGIC:
            do_macho(file, 32, BIG_ENDIAN)
        elif magic == MH_CIGAM:
            do_macho(file, 32, LITTLE_ENDIAN)
        elif magic == MH_MAGIC_64:
            do_macho(file, 64, BIG_ENDIAN)
        elif magic == MH_CIGAM_64:

def __init__(self, fileobj, start=0, size=maxint):
        if isinstance(fileobj, fileview):
            self._fileobj = fileobj._fileobj
        else:
            self._fileobj = fileobj
        self._start = start
        self._end = start + size
        self._pos = 0

def __init__(self, fileobj, start=0, size=maxint):
        if isinstance(fileobj, fileview):
            self._fileobj = fileobj._fileobj
        else:
            self._fileobj = fileobj
        self._start = start
        self._end = start + size
        self._pos = 0