def validate_config(self, config):
        """We only validate the config if passed.

        Also we use the ExperimentSpecification to check if this config was
        intended as an experiment.
        """
        # config is optional
        if not config:
            return config

        spec = validate_experiment_spec_config(config)

        if spec.is_experiment:
            # Resume normal creation
            return config

        # Raise an error to tell the user to use experiment creation instead
        raise ValidationError('Current experiment creation could not be performed.\n'
                              'The reason is that the specification sent correspond '
                              'to a `{}`.\n'.format(spec.kind))
We only validate the config if passed.

        Also we use the ExperimentSpecification to check if this config was
        intended as an experiment.