diff --git a/src/list/raxos/protocal/src/apaxos/history.rs b/src/list/raxos/protocal/src/apaxos/history.rs
index f8c474a..5957bef 100644
--- a/src/list/raxos/protocal/src/apaxos/history.rs
+++ b/src/list/raxos/protocal/src/apaxos/history.rs
@@ -55,18 +55,6 @@ where
     /// All `maximal` have no order between them.
     fn maximals(&self) -> impl Iterator<Item = (T::Time, T::Event)>;
 
-    fn do_merge(&mut self, other: Self);
-
-    fn maximal_times<'a>(&'a self) -> impl Iterator<Item = T::Time> + 'a
-    where Self: sealed::Seal {
-        self.maximals().map(|(t, _)| t)
-    }
-
-    fn merge_view(&mut self, view: HistoryView<T>)
-    where Self: sealed::Seal {
-        self.merge(view.into_history());
-    }
-
     /// Merge two [`History`]
     ///
     /// Note that if there are `maximal` that have an order, the smaller one
@@ -92,6 +80,13 @@ where
         *self = res;
     }
 
+    fn do_merge(&mut self, other: Self);
+
+    fn maximal_times<'a>(&'a self) -> impl Iterator<Item = T::Time> + 'a
+    where Self: sealed::Seal {
+        self.maximals().map(|(t, _)| t)
+    }
+
     /// Check if a [`History`] is greater or equal to a given time.
     ///
     /// In other word, if there is a [`Time`] in this history that is greater or
diff --git a/src/list/raxos/protocal/src/commonly_used/history/linear.rs b/src/list/raxos/protocal/src/commonly_used/history/linear.rs
index 4e872f3..39ac6c6 100644
--- a/src/list/raxos/protocal/src/commonly_used/history/linear.rs
+++ b/src/list/raxos/protocal/src/commonly_used/history/linear.rs
@@ -4,8 +4,8 @@ use crate::apaxos::history::History;
 use crate::Types;
 
 pub type Mode = bool;
-pub const SINGLE_LOG: Mode = false;
-pub const MULTI_LOG: Mode = true;
+pub const SINGLE_VALUE: Mode = false;
+pub const MULTI_VALUE: Mode = true;
 
 #[derive(Clone, Debug)]
 pub struct LinearHistory<T: Types, const MODE: Mode> {
@@ -43,22 +43,22 @@ where
     T::Time: Ord,
 {
     fn do_append(&mut self, time: T::Time, event: T::Event) {
-        // In a single log mode, it disallows to append new event if there is already
-        // one. Because the history can not be changed.
+        // In a single value mode(such as classic paxos),
+        // it disallows to append new event if there is already one.
+        // Because the history can not be changed.
         // In such case, just use the last value.
-        match MODE {
-            SINGLE_LOG => {
-                if let Some(last) = self.time_events.last_key_value() {
-                    let v = last.1.clone();
-                    self.time_events.insert(time, v);
+        let ev = match MODE {
+            SINGLE_VALUE => {
+                if let Some((_t, ev)) = self.time_events.last_key_value() {
+                    ev.clone()
                 } else {
-                    self.time_events.insert(time, event);
+                    event
                 }
             }
-            MULTI_LOG => {
-                self.time_events.insert(time, event);
-            }
-        }
+            MULTI_VALUE => event,
+        };
+
+        self.time_events.insert(time, ev);
     }
 
     fn get(&self, time: &T::Time) -> Option<&T::Event> {
diff --git a/src/list/raxos/protocal/src/implementations/paxos.rs b/src/list/raxos/protocal/src/implementations/paxos.rs
index 5d67b1a..c2604b2 100644
--- a/src/list/raxos/protocal/src/implementations/paxos.rs
+++ b/src/list/raxos/protocal/src/implementations/paxos.rs
@@ -8,7 +8,7 @@
 //!   the one with max `v_ballot`.
 
 use crate::commonly_used::history::linear::LinearHistory;
-use crate::commonly_used::history::linear::SINGLE_LOG;
+use crate::commonly_used::history::linear::SINGLE_VALUE;
 use crate::commonly_used::quorum_set::majority::Majority;
 use crate::commonly_used::transport::DirectCall;
 use crate::Types;
@@ -20,9 +20,9 @@ struct Paxos {}
 impl Types for Paxos {
     type Time = u64;
     type Event = String;
-    type History = LinearHistory<Paxos, { SINGLE_LOG }>;
-    type QuorumSet = Majority<Paxos>;
-    type Transport = DirectCall<Paxos>;
+    type History = LinearHistory<Self, { SINGLE_VALUE }>;
+    type QuorumSet = Majority<Self>;
+    type Transport = DirectCall<Self>;
 }
 
 #[cfg(test)]