Resolve a concrete domain for ``pipeline``.

def resolve_domain(self, pipeline):
        """Resolve a concrete domain for ``pipeline``.
        """
        domain = pipeline.domain(default=self._default_domain)
        if domain is GENERIC:
            raise ValueError(
                "Unable to determine domain for Pipeline.\n"
                "Pass domain=<desired domain> to your Pipeline to set a "
                "domain."
            )
        return domain