[Beta] Fetch the model referenced by ``model_ref``.

         Args:
            model_ref (Union[ \
                :class:`~google.cloud.bigquery.model.ModelReference`, \
                str, \
            ]):
                A reference to the model to fetch from the BigQuery API.
                If a string is passed in, this method attempts to create a
                model reference from a string using
                :func:`google.cloud.bigquery.model.ModelReference.from_string`.
            retry (:class:`google.api_core.retry.Retry`):
                (Optional) How to retry the RPC.

         Returns:
            google.cloud.bigquery.model.Model:
                A ``Model`` instance.

def get_model(self, model_ref, retry=DEFAULT_RETRY):
        """[Beta] Fetch the model referenced by ``model_ref``.

         Args:
            model_ref (Union[ \
                :class:`~google.cloud.bigquery.model.ModelReference`, \
                str, \
            ]):
                A reference to the model to fetch from the BigQuery API.
                If a string is passed in, this method attempts to create a
                model reference from a string using
                :func:`google.cloud.bigquery.model.ModelReference.from_string`.
            retry (:class:`google.api_core.retry.Retry`):
                (Optional) How to retry the RPC.

         Returns:
            google.cloud.bigquery.model.Model:
                A ``Model`` instance.
        """
        if isinstance(model_ref, str):
            model_ref = ModelReference.from_string(
                model_ref, default_project=self.project
            )

        api_response = self._call_api(retry, method="GET", path=model_ref.path)
        return Model.from_api_repr(api_response)