def checksum(self, new_val=None):
    '\n        Set or check the checksum status of this CDF. If checksums\n        are enabled, the checksum will be verified every time the file\n        is opened.\n\n        Other Parameters\n        ================\n        new_val : boolean\n            True to enable checksum, False to disable, or leave out\n            to simply check.\n\n        Returns\n        =======\n        out : boolean\n            True if the checksum is enabled or False if disabled\n        '
    if (new_val != None):
        self._call(const.PUT_, const.CDF_CHECKSUM_, (const.MD5_CHECKSUM if new_val else const.NO_CHECKSUM))
    chk = ctypes.c_long(0)
    self._call(const.GET_, const.CDF_CHECKSUM_, ctypes.byref(chk))
    if (not (chk.value in (const.MD5_CHECKSUM.value, const.NO_CHECKSUM.value))):
        raise CDFError(const.BAD_CHECKSUM)
    return (chk.value == const.MD5_CHECKSUM.value)
Set or check the checksum status of this CDF. If checksums
are enabled, the checksum will be verified every time the file
is opened.

Other Parameters
================
new_val : boolean
    True to enable checksum, False to disable, or leave out
    to simply check.

Returns
=======
out : boolean
    True if the checksum is enabled or False if disabled
def checksum(self, new_val=None):
    '\n        Set or check the checksum status of this CDF. If checksums\n        are enabled, the checksum will be verified every time the file\n        is opened.\n\n        Other Parameters\n        ================\n        new_val : boolean\n            True to enable checksum, False to disable, or leave out\n            to simply check.\n\n        Returns\n        =======\n        out : boolean\n            True if the checksum is enabled or False if disabled\n        '
    if (new_val != None):
        self._call(const.PUT_, const.CDF_CHECKSUM_, (const.MD5_CHECKSUM if new_val else const.NO_CHECKSUM))
    chk = ctypes.c_long(0)
    self._call(const.GET_, const.CDF_CHECKSUM_, ctypes.byref(chk))
    if (not (chk.value in (const.MD5_CHECKSUM.value, const.NO_CHECKSUM.value))):
        raise CDFError(const.BAD_CHECKSUM)
    return (chk.value == const.MD5_CHECKSUM.value)