def _fileUrandom(self, nbytes):
        for src in self.randomSources:
            try:
                f = file(src, 'rb')
            except (IOError, OSError):
                pass
            else:
                bytes = f.read(nbytes)
                f.close()
                return bytes
        raise SourceNotAvailable("File sources not available: %s" %
                                 (self.randomSources,))
Remove empty keys for a :class:`Model` from the database. No
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/python/randbytes.py/RandomFactory._fileUrandom--crossover with--dataset/ETHPy150Open lsbardel/python-stdnet/stdnet/odm/session.py/Session.clean