diff --git a/src/interface.jl b/src/interface.jl
index 5b4e88e..e142230 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -47,17 +47,17 @@ julia>
 # Signature
 """
 function runMCTS(
-  initialState,
+  initialstate,
   transition::Function,
-  args...,
+  transitionargs::NamedTuple,
   ;
   totalsample::Integer=3, 
-  maxDepth::Integer=3, 
+  maxdepth::Integer=3, 
   maxiterations::Integer=10, 
   explorationweight::Number=1.0,
   )
   
-  root = MCTSNode("root", initialState, 0, 0, 0, 0, false, nothing, Dict{String, MCTSNode}())
+  root = MCTSNode("root", initialstate, 0, 0, 0, 0, false, nothing, Dict{String, MCTSNode}())
 
   for nth in 1:maxiterations
     node = root
@@ -71,11 +71,11 @@ function runMCTS(
       # do nothing then go directly to backpropagation
       backpropagate(leafNode, node.reward)
     else
-      expand(node, transition, args...; 
+      expand(node, transition, transitionargs; 
             totalsample=totalsample)
       leafNode = selectChildNode(node)
-      simTrajectoryReward, terminalstate = simulate(leafNode, transition, args...; 
-                                                  maxDepth=maxDepth, totalsample=totalsample)
+      simTrajectoryReward, terminalstate = simulate(leafNode, transition, transitionargs; 
+                                                  maxdepth=maxdepth, totalsample=totalsample)
       if terminalstate !== nothing  #XXX not sure why I need this 
         terminalstate[:totalTrajectoryReward] = simTrajectoryReward
       end
diff --git a/src/mcts.jl b/src/mcts.jl
index 47f7d34..1896444 100644
--- a/src/mcts.jl
+++ b/src/mcts.jl
@@ -244,13 +244,13 @@ julia>
 
 # Signature
 """
-function expand(node::MCTSNode,transition::Function, args...; totalsample::Integer=3)
+function expand(node::MCTSNode,transition::Function, args::NamedTuple; totalsample::Integer=3)
 
   nthSample = 0
   while true
     nthSample += 1
     if nthSample <= totalsample
-      newNodeKey, newstate, progressvalue = transition(node.state, args...)
+      newNodeKey, newstate, progressvalue = transition(node.state, args)
       if newNodeKey ∉ keys(node.children)
         node.children[newNodeKey] = 
           MCTSNode(newNodeKey, newstate, 0, progressvalue, 0, newstate[:reward], 
@@ -287,19 +287,19 @@ julia>
 # Signature
 """
 function simulate(node::MCTSNode, transition::Function, args...; 
-  maxDepth::Integer=3, totalsample::Integer=3
+  maxdepth::Integer=3, totalsample::Integer=3
   )::Union{Tuple{Number, Dict{Symbol, <:Any}}, Tuple{Number, Nothing}}
 
   simTrajectoryReward = 0.0
   terminalstate = nothing
   
-  for depth in 1:maxDepth
+  for depth in 1:maxdepth
     simTrajectoryReward += node.reward
     if node.isterminal
       terminalstate = node.state
       break
     else
-      expand(node, transition, args...; 
+      expand(node, transition, args;
             totalsample=totalsample)
       node = selectChildNode(node)
     end