docs: 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