def scan(self, file_or_stream):
        """
        :param file_or_stream: :class:`Blob` instance, filename or file object

        :returns: True if file is 'clean', False if a virus is detected, None if
        file could not be scanned.

        If `file_or_stream` is a Blob, scan result is stored in
        Blob.meta['antivirus'].
        """
        if not clamd:
            return None

        res = self._scan(file_or_stream)
        if isinstance(file_or_stream, Blob):
            file_or_stream.meta["antivirus"] = res
        return res
:param file_or_stream: :class:`Blob` instance, filename or file object

        :returns: True if file is 'clean', False if a virus is detected, None if
        file could not be scanned.

        If `file_or_stream` is a Blob, scan result is stored in
        Blob.meta['antivirus'].