Retrieves portal object according to 'portal_name' and
        returns its cik.

def get_portal_cik(self, portal_name):
        """ Retrieves portal object according to 'portal_name' and
        returns its cik. """
        portal = self.get_portal_by_name(portal_name)
        cik = portal[2][1]['info']['key']
        return cik