'Check that the SC is there and being managed by EM.
:returns: The SC SSN.
:raises VolumeBackendAPIException:'

def find_sc(self, ssn=(-1)):

    ssn = self._vet_ssn(ssn)
    r = self.client.get('StorageCenter/StorageCenter')
    result = self._get_result(r, 'scSerialNumber', ssn)
    if (result is None):
        LOG.error('Failed    to    find    %(s)s.        Result    %(r)s', {'s': ssn, 'r': r})
        raise exception.VolumeBackendAPIException(data=_('Failed    to    find    Storage    Center'))
    return self._get_id(result)
