docs: def _check_status(sdp_state):
      """SDP Status check.
  
      Do all the tests to determine, if the SDP state is
      "broken", what could be the cause, and return a
      suitable status message to be sent back by the calling
      function.
      """
      try:
          errval = "error"
          errdict = dict(state="unknown", reason="unknown")
          if sdp_state.current_state == "unknown":
              errdict['reason'] = 'database not initialised.'
              LOG.debug('Current state is unknown;')
              LOG.debug('Target state is %s;', sdp_state.target_state)
              LOG.debug('Current state timestamp is %s;',
                        sdp_state.current_timestamp)
          elif sdp_state.current_state is None:
              errdict['reason'] = 'Master Controller Services may have died.'
              LOG.debug('Current state is NONE;')
              LOG.debug('Target state is %s;', sdp_state.target_state)
              LOG.debug('Current state timestamp is %s;',
                        sdp_state.current_timestamp)
          elif sdp_state.target_state is None:
              errdict['reason'] = 'Master Controller Services may have died.'
              LOG.debug('Current state is  %s;',
                        sdp_state.current_state)
              LOG.debug('Target state is NONE;')
              LOG.debug('Current state timestamp is %s;',
                        sdp_state.current_timestamp)
              LOG.debug('Target state timestamp is %s;',
                        sdp_state.target_timestamp)
          elif sdp_state.current_timestamp is None:
              errdict['reason'] = 'Master Controller Services may have died.'
              LOG.debug('Current state is  %s;',
                        sdp_state.current_state)
              LOG.debug('Target state is %s;', sdp_state.target_state)
              LOG.debug('Current state timestamp is NONE')
              LOG.debug('Target state timestamp is %s;',
                        sdp_state.target_timestamp)
          elif sdp_state.target_timestamp is None:
              errdict['reason'] = 'Master Controller Services may have died.'
              LOG.debug('Current state is  %s;',
                        sdp_state.current_state)
              LOG.debug('Target state is %s;', sdp_state.target_state)
              LOG.debug('Current state timestamp is %s;',
                        sdp_state.current_timestamp)
              LOG.debug('Target state timestamp is NONE')
          elif sdp_state.current_timestamp < sdp_state.target_timestamp:
              errdict['reason'] = \
                  'Timestamp for Master Controller Services is stale.'
              LOG.debug('Current state is  %s;',
                        sdp_state.current_state)
              LOG.debug('Target state is %s;', sdp_state.target_state)
              LOG.debug('Current state timestamp is %s;',
                        sdp_state.current_timestamp)
              LOG.debug('Target state timestamp is %s;',
                        sdp_state.target_timestamp)
          else:
              errval = "okay"
      except ConnectionError as err:
          errdict['reason'] = err
          LOG.debug('Connection Error %s', err)
      return errval, errdict