def nodes_update_facts_since(timestamp)
      ts = (timestamp.is_a?(String) ? Time.iso8601(ts) : timestamp)
      node_properties.delete_if do |_k, data|
        # in '/v3/nodes' we must take 'facts-timestamp'
        !data["facts_timestamp"] || Time.iso8601(data["facts_timestamp"]) < ts
      end.keys
    end
def nodes_update_facts_since(timestamp)
      ts = (timestamp.is_a?(String) ? Time.iso8601(ts) : timestamp)
      node_properties.delete_if do |_k, data|
        # in '/v3/nodes' we must take 'facts-timestamp'
        !data["facts_timestamp"] || Time.iso8601(data["facts_timestamp"]) < ts
      end.keys
    end
get all nodes that have updated facts