'Add custom metadata to the output.
:param dict infos: a Python dictionary where each key is a field
and each value is your new metadata.'

def addMetadata(self, infos):

    args = {}
    for (key, value) in list(infos.items()):
        args[NameObject(key)] = createStringObject(value)
    self.getObject(self._info).update(args)
