Get the input of a submission. If only_input is False, returns the full submissions with a dictionnary object at the key "input".
            Else, returns only the dictionnary.

def get_input_from_submission(self, submission, only_input=False):
        """
            Get the input of a submission. If only_input is False, returns the full submissions with a dictionnary object at the key "input".
            Else, returns only the dictionnary.
        """
        inp = bson.BSON.decode(self._gridfs.get(submission['input']).read())
        if only_input:
            return inp
        else:
            submission["input"] = inp
            return submission