Fetch grants from a remote OAI-PMH endpoint.

        Return the Sickle-provided generator object.

def iter_grants(self, as_json=True):
        """Fetch grants from a remote OAI-PMH endpoint.

        Return the Sickle-provided generator object.
        """
        records = self.client.ListRecords(metadataPrefix='oaf',
                                          set=self.setspec)
        for rec in records:
            try:
                grant_out = rec.raw  # rec.raw is XML
                if as_json:
                    grant_out = self.grantxml2json(grant_out)
                yield grant_out
            except FunderNotFoundError as e:
                current_app.logger.warning("Funder '{0}' not found.".format(
                    e.funder_id))