code: async def cluster_require_full_coverage(self, nodes_cache):
          
          nodes = nodes_cache or self.nodes
  
          async def node_require_full_coverage(node):
              r_node = self.get_redis_link(host=node['host'], port=node['port'])
              node_config = await r_node.config_get('cluster-require-full-coverage')
              return 'yes' in node_config.values()
  
          # at least one node should have cluster-require-full-coverage yes
          for node in nodes.values():
              if await node_require_full_coverage(node):
                  return True
          return False
docs: if exists 'cluster-require-full-coverage no' config on redis servers,
          then even all slots are not covered, cluster still will be able to
          respond