code: def GET_subdomains( self, path_info ):
          
          qs_values = path_info['qs_values']
          page = qs_values.get('page', None)
          if page is None:
              log.error("Page required")
              return self._reply_json({'error': 'page= argument required'}, status_code=400)
  
          try:
              page = int(page)
              assert page >= 0
          except Exception:
              log.error("Invalid page")
              return self._reply_json({'error': 'Invalid page= value'}, status_code=400)
  
          offset = page * 100
          count = 100
  
          blockstackd_url = get_blockstackd_url()
          res = blockstackd_client.get_all_subdomains(offset, count, hostport=blockstackd_url)
  
          if json_is_error(res):
              log.error("Failed to list all subdomains (offset={}, count={}): {}".format(offset, count, res['error']))
              return self._reply_json({'error': 'Failed to list all names'}, status_code=res.get('http_status', 406))
  
          return self._reply_json(res)
docs: Get all subdomains in existence.
          Requires page={int}
          Returns the list on success
          Returns 400 on invalid arguments
          Returns 502 on failure to get names