diff --git a/api.lua b/api.lua
index 51d1ff9..48962c1 100644
--- a/api.lua
+++ b/api.lua
@@ -7,7 +7,7 @@ local _aux = maidroid._aux
 
 -- aux function to generate serialnumber for inventories
 local gen_inv_serialnumber = (function ()
-  local serialnumber = 0  
+  local serialnumber = 0
   return function ()
     serialnumber = serialnumber + 1
     return serialnumber - 1
@@ -55,75 +55,75 @@ function maidroid.register_maidroid(product_name, def)
     makes_footstep_sound = true,
     module = nil,
     invname = "",
-    
+
     on_activate = function(self, staticdata)
       self.invname = "maidroid"..tostring(gen_inv_serialnumber())
       local inv = minetest.create_detached_inventory(self.invname, {
         on_put = function(inv, listname, index, stack, player)
-	  if listname == module_invname then
-	    local module_name = stack:get_name()
-	    local module_def = maidroid.registered_modules[module_name]
-	    self.module = module_def
-	    module_def.initialize(self)
-	  end
-	end,
-	allow_put = function(inv, listname, index, stack, player)
-	  local item_name = stack:get_name()
-	  local is_module = maidroid.registered_modules[item_name]
-	  if listname == main_invname
-	  or (listname == module_invname and is_module) then
-	    return stack:get_count()
-	  end
-	  return 0
-	end,
-	on_take = function(inv, listname, index, stack, player)
-	  if listname == module_invname then
-	    local module_name = stack:get_name()
-	    local module_def = maidroid.registered_modules[module_name]
-	    self.module = nil
-	    module_def.finalize(self)
-	  end
-	end,
+          if listname == module_invname then
+            local module_name = stack:get_name()
+            local module_def = maidroid.registered_modules[module_name]
+            self.module = module_def
+            module_def.initialize(self)
+          end
+        end,
+        allow_put = function(inv, listname, index, stack, player)
+          local item_name = stack:get_name()
+          local is_module = maidroid.registered_modules[item_name]
+          if listname == main_invname
+          or (listname == module_invname and is_module) then
+            return stack:get_count()
+          end
+          return 0
+        end,
+        on_take = function(inv, listname, index, stack, player)
+          if listname == module_invname then
+            local module_name = stack:get_name()
+            local module_def = maidroid.registered_modules[module_name]
+            self.module = nil
+            module_def.finalize(self)
+          end
+        end,
       })
       inv:set_size(main_invname, main_invsize)
       inv:set_size(module_invname, module_invsize)
       -- process staticdata
       if staticdata ~= "" then
-	local data = minetest.deserialize(staticdata)
-	if data.inv.module ~= "" then
-	  module_stack = ItemStack(data.inv.module)
-	  module_stack:set_count(1)
-	  inv:add_item(module_invname, module_stack)
-	  self.module = maidroid.registered_modules[data.inv.module]
-	end
-	for _, item in ipairs(data.inv.main) do
-	  local itemstack = ItemStack(item.name)
-	  itemstack:set_count(item.count)
-	  inv:add_item(main_invname, itemstack)
-	end
+        local data = minetest.deserialize(staticdata)
+        if data.inv.module ~= "" then
+          module_stack = ItemStack(data.inv.module)
+          module_stack:set_count(1)
+          inv:add_item(module_invname, module_stack)
+          self.module = maidroid.registered_modules[data.inv.module]
+        end
+        for _, item in ipairs(data.inv.main) do
+          local itemstack = ItemStack(item.name)
+          itemstack:set_count(item.count)
+          inv:add_item(main_invname, itemstack)
+        end
       end
       -- initialize module
       if self.module then self.module.initialize(self)
       else self.object:setvelocity{x = 0, y = 0, z = 0} end
     end,
-    
+
     on_step = function(self, dtime)
       if self.module then self.module.on_step(self, dtime) end
     end,
-    
+
     on_punch = function(self, puncher, time_from_last_punch, tool_capabilities, dir)
     end,
-    
+
     on_rightclick = function(self, clicker)
       local formspec = "size[8,9]"
-	.."list[detached:"..self.invname..";"..main_invname..";0,0;4,4;]"
-	.."label[5,0;MODULE]"
-	.."list[detached:"..self.invname..";"..module_invname..";6,0;1,1;]"
-	.."list[current_player;"..main_invname..";0,5;8,1;]"
-	.."list[current_player;"..main_invname..";0,6.2;8,3;8]"
+      .."list[detached:"..self.invname..";"..main_invname..";0,0;4,4;]"
+      .."label[5,0;MODULE]"
+      .."list[detached:"..self.invname..";"..module_invname..";6,0;1,1;]"
+      .."list[current_player;"..main_invname..";0,5;8,1;]"
+      .."list[current_player;"..main_invname..";0,6.2;8,3;8]"
       minetest.show_formspec(clicker:get_player_name(), self.invname, formspec)
     end,
-    
+
     get_staticdata = function(self)
       local inv = _aux.get_maidroid_inventory(self)
       local staticdata = {}
@@ -132,17 +132,17 @@ function maidroid.register_maidroid(product_name, def)
       staticdata.inv.module = module_name or ""
       staticdata.inv.main = {}
       for _, item in ipairs(inv:get_list(main_invname)) do
-	local count = item:get_count()
-	local itemname = item:get_name()
-	if count ~= 0 then
-	  local itemdata = { count = count, name = itemname }
-	  table.insert(staticdata.inv.main, itemdata)
-	end
+        local count = item:get_count()
+        local itemname = item:get_name()
+        if count ~= 0 then
+          local itemdata = { count = count, name = itemname }
+          table.insert(staticdata.inv.main, itemdata)
+        end
       end
       return minetest.serialize(staticdata)
     end,
   })
-  
+
   -- register spawn egg
   minetest.register_craftitem(product_name.."_spawn_egg", {
     description = def.description.." Spawn Egg",
@@ -151,8 +151,8 @@ function maidroid.register_maidroid(product_name, def)
     on_use = function(itemstack, user, pointed_thing)
       print(pointed_thing.under, pointed_thing.above)
       if pointed_thing.above ~= nil then
-	minetest.add_entity(pointed_thing.above, product_name)
-	return itemstack
+        minetest.add_entity(pointed_thing.above, product_name)
+        return itemstack
       end
       return nil
     end
diff --git a/modules/_aux.lua b/modules/_aux.lua
index 4a52c48..2ed6840 100644
--- a/modules/_aux.lua
+++ b/modules/_aux.lua
@@ -50,14 +50,14 @@ function maidroid.modules._aux.pickup_item(self, radius, target_pred)
     if not obj:is_player() and obj:get_luaentity() then
       local itemstring = obj:get_luaentity().itemstring
       if itemstring then
-	if pred(itemstring) then
-	  local inv = maidroid._aux.get_maidroid_inventory(self)
-	  local stack = ItemStack(itemstring)
-	  local leftover = inv:add_item("main", stack)
-	  minetest.add_item(obj:getpos(), leftover)
-	  obj:get_luaentity().itemstring = ""
-	  obj:remove()
-	end
+        if pred(itemstring) then
+          local inv = maidroid._aux.get_maidroid_inventory(self)
+          local stack = ItemStack(itemstring)
+          local leftover = inv:add_item("main", stack)
+          minetest.add_item(obj:getpos(), leftover)
+          obj:get_luaentity().itemstring = ""
+          obj:remove()
+        end
       end
     end
   end
diff --git a/modules/chasing_player_module.lua b/modules/chasing_player_module.lua
index 84e2dab..f720319 100644
--- a/modules/chasing_player_module.lua
+++ b/modules/chasing_player_module.lua
@@ -7,24 +7,24 @@ local util = maidroid.util
 local _aux = maidroid.modules._aux
 
 local state = { idle = 0, chase = 1}
-local view_of_range = 7 
-local stop_of_range = 2 
+local view_of_range = 7
+local stop_of_range = 2
 
 maidroid.register_module("maidroid:chasing_player_module", {
   description = "Maidroid Module : Chasing Player",
   inventory_image = "maidroid_chasing_player_module.png",
-  
+
   initialize = function(self)
     self.state = state.idle
     self.object:setacceleration{x = 0, y = -10, z = 0}
     self.object:setvelocity{x = 0, y = 0, z = 0}
   end,
-  
+
   finalize = function(self)
     self.state = nil
     self.object:setvelocity{x = 0, y = 0, z = 0}
   end,
-  
+
   on_step = function(self, dtime)
     local pos = self.object:getpos()
     local all_objects = minetest.get_objects_inside_radius(pos, view_of_range)
@@ -42,33 +42,33 @@ maidroid.register_module("maidroid:chasing_player_module", {
     local vel = self.object:getvelocity()
     if (vector.length(dir) < stop_of_range) then
       if self.state == state.chase then
-	self.object:set_animation(maidroid.animations.stand, 15, 0)
-	self.state = state.idle
-	self.object:setvelocity({x = 0, y = vel.y, z = 0})
+        self.object:set_animation(maidroid.animations.stand, 15, 0)
+        self.state = state.idle
+        self.object:setvelocity({x = 0, y = vel.y, z = 0})
       end
     else
       if self.state == state.idle then
-	self.object:set_animation(maidroid.animations.walk, 15, 0)
-	self.state = state.chase
+        self.object:set_animation(maidroid.animations.walk, 15, 0)
+        self.state = state.chase
       end
       self.object:setvelocity({x = dir.x, y = vel.y, z = dir.z})
     end
     local yaw = math.atan2(dir.z, dir.x) + math.pi/2
     self.object:setyaw(yaw)
-    
+
     -- jump process
     if vel.y == 0 and self.state == state.chase then
       local rdir = vector.round(dir)
       local front_vec = { x = 0, y = 0, z = 0 }
       if math.abs((rdir.x / (math.abs(rdir.x) + math.abs(rdir.z)))) > 0.5 then
-	if rdir.x > 0 then front_vec.x = 1 else front_vec.x = -1 end
+        if rdir.x > 0 then front_vec.x = 1 else front_vec.x = -1 end
       end
       if math.abs((rdir.z / (math.abs(rdir.x) + math.abs(rdir.z)))) > 0.5 then
-	if rdir.z > 0 then front_vec.z = 1 else front_vec.z = -1 end
+        if rdir.z > 0 then front_vec.z = 1 else front_vec.z = -1 end
       end
       local front_pos = vector.add(vector.round(pos), front_vec)
       if minetest.get_node(front_pos).name ~= "air" then
-	self.object:setvelocity({x = dir.x, y = 5, z = dir.z})
+        self.object:setvelocity({x = dir.x, y = 5, z = dir.z})
       end
     end
   end,
diff --git a/modules/farming_module.lua b/modules/farming_module.lua
index f00a681..8ff8470 100644
--- a/modules/farming_module.lua
+++ b/modules/farming_module.lua
@@ -40,7 +40,7 @@ end
 maidroid.register_module("maidroid:farming_module", {
   description = "Maidroid Module : Farming",
   inventory_image = "maidroid_farming_module.png",
-  
+
   initialize = function(self)
     self.object:set_animation(maidroid.animations.walk, 15, 0)
     self.object:setacceleration{x = 0, y = -10, z = 0}
@@ -49,14 +49,14 @@ maidroid.register_module("maidroid:farming_module", {
     self.time_count = 0
     _aux.change_dir(self)
   end,
-  
+
   finalize = function(self)
     self.state = nil
     self.preposition = nil
     self.time_count = nil
     self.object:setvelocity{x = 0, y = 0, z = 0}
   end,
-  
+
   on_step = function(self, dtime)
     local pos = self.object:getpos()
     local rpos = vector.round(pos)
@@ -66,70 +66,70 @@ maidroid.register_module("maidroid:farming_module", {
     local forward_pos = vector.add(rpos, forward_vec2)
     local forward_node = minetest.get_node(forward_pos)
     local forward_under_pos = vector.subtract(forward_pos, {x = 0, y = 1, z = 0})
-    
+
     if self.state == state.walk then -- searching plants or spaces
       if maidroid.util.table_find_value(target_plants_list, forward_node.name) then
-	self.state = state.punch
-	self.object:set_animation(maidroid.animations.mine, 15, 0)
-	self.object:setvelocity{x = 0, y = 0, z = 0}
+        self.state = state.punch
+        self.object:set_animation(maidroid.animations.mine, 15, 0)
+        self.object:setvelocity{x = 0, y = 0, z = 0}
       elseif pos.x == self.preposition.x or pos.z == self.preposition.z then
-	_aux.change_dir(self)
+        _aux.change_dir(self)
       elseif forward_node.name == "air"
-      and minetest.get_item_group(minetest.get_node(forward_under_pos).name, "wet") > 0
-      and has_seed_item(self) then
-	self.state = state.plant
-	self.object:set_animation(maidroid.animations.mine, 15, 0)
-	self.object:setvelocity{x = 0, y = 0, z = 0}
-      end
-      -- pickup droped seed items
-      _aux.pickup_item(self, 1.5, function(itemstring)
-        return minetest.get_item_group(itemstring, "seed") > 0
-      end)
-      
-    elseif self.state == state.punch then
-      if self.time_count >= max_punch_time then
-	if maidroid.util.table_find_value(target_plants_list, forward_node.name) then
-	  minetest.remove_node(forward_pos)
-	  local inv = minetest.get_inventory{type = "detached", name = self.invname}
-	  local stacks = minetest.get_node_drops(forward_node.name)
-	  for _, stack in ipairs(stacks) do
-	    local leftover = inv:add_item("main", stack)
-	    minetest.add_item(forward_pos, leftover)
-	  end
-	end
-	self.state = state.walk
-	self.object:set_animation(maidroid.animations.walk, 15, 0)
-	self.time_count = 0
-	_aux.change_dir(self)
-      else
-	self.time_count = self.time_count + 1
-      end
-      
-    elseif self.state == state.plant then
-      if self.time_count >= max_plant_time then
-	if forward_node.name == "air" and minetest.get_item_group(
+        and minetest.get_item_group(minetest.get_node(forward_under_pos).name, "wet") > 0
+        and has_seed_item(self) then
+          self.state = state.plant
+          self.object:set_animation(maidroid.animations.mine, 15, 0)
+          self.object:setvelocity{x = 0, y = 0, z = 0}
+        end
+        -- pickup droped seed items
+        _aux.pickup_item(self, 1.5, function(itemstring)
+          return minetest.get_item_group(itemstring, "seed") > 0
+        end)
+
+      elseif self.state == state.punch then
+        if self.time_count >= max_punch_time then
+          if maidroid.util.table_find_value(target_plants_list, forward_node.name) then
+            minetest.remove_node(forward_pos)
+            local inv = minetest.get_inventory{type = "detached", name = self.invname}
+            local stacks = minetest.get_node_drops(forward_node.name)
+            for _, stack in ipairs(stacks) do
+              local leftover = inv:add_item("main", stack)
+              minetest.add_item(forward_pos, leftover)
+            end
+          end
+          self.state = state.walk
+          self.object:set_animation(maidroid.animations.walk, 15, 0)
+          self.time_count = 0
+          _aux.change_dir(self)
+        else
+          self.time_count = self.time_count + 1
+        end
+        
+      elseif self.state == state.plant then
+        if self.time_count >= max_plant_time then
+          if forward_node.name == "air" and minetest.get_item_group(
           minetest.get_node(forward_under_pos).name, "soil") > 0 then
-	  local inv = minetest.get_inventory{type = "detached", name = self.invname}
-	  local stacks = inv:get_list("main")
-	  for idx, stack in ipairs(stacks) do
-	    local item_name = stack:get_name()
-	    if minetest.get_item_group(item_name, "seed") > 0 then
-	      minetest.add_node(forward_pos, {name = item_name, param2 = 1})
-	      stack:take_item(1)
-	      inv:set_stack("main", idx, stack)
-	      break
-	    end
-	  end
-	end
-	self.state = state.walk
-	self.object:set_animation(maidroid.animations.walk, 15, 0)
-	self.time_count = 0
-	_aux.change_dir(self)
-      else
-	self.time_count = self.time_count + 1
+            local inv = minetest.get_inventory{type = "detached", name = self.invname}
+            local stacks = inv:get_list("main")
+            for idx, stack in ipairs(stacks) do
+              local item_name = stack:get_name()
+              if minetest.get_item_group(item_name, "seed") > 0 then
+                minetest.add_node(forward_pos, {name = item_name, param2 = 1})
+                stack:take_item(1)
+                inv:set_stack("main", idx, stack)
+                break
+              end
+            end
+          end
+          self.state = state.walk
+          self.object:set_animation(maidroid.animations.walk, 15, 0)
+          self.time_count = 0
+          _aux.change_dir(self)
+        else
+          self.time_count = self.time_count + 1
+        end
       end
+      self.preposition = pos
+      return
     end
-    self.preposition = pos
-    return
-  end
-})
+  })
diff --git a/modules/lumberjack_module.lua b/modules/lumberjack_module.lua
index f737863..25faafd 100644
--- a/modules/lumberjack_module.lua
+++ b/modules/lumberjack_module.lua
@@ -41,7 +41,7 @@ end
 maidroid.register_module("maidroid:lumberjack_module", {
   description = "Maidroid Module : Lumberjack",
   inventory_image = "maidroid_lumberjack_module.png",
-  
+
   initialize = function(self)
     self.state = state.walk
     self.time_count = 0
@@ -50,14 +50,14 @@ maidroid.register_module("maidroid:lumberjack_module", {
     self.preposition = self.object:getpos()
     _aux.change_dir(self)
   end,
-  
+
   finalize = function(self)
     self.state = nil
     self.time_count = nil
     self.preposition = nil
     self.object:setvelocity{x = 0, y = 0, z = 0}
   end,
-  
+
   on_step = function(self, dtime)
     local pos = self.object:getpos()
     local rpos = vector.round(pos)
@@ -68,74 +68,74 @@ maidroid.register_module("maidroid:lumberjack_module", {
     local forward_node = minetest.get_node(forward_pos)
     local forward_under_pos = _aux.get_under_pos(forward_pos)
     local forward_under_node = minetest.get_node(forward_under_pos)
-    
+
     if self.state == state.walk then
       if check_punch_flag(forward_pos) then -- punch tree node
-	self.state = state.punch
-	self.object:set_animation(maidroid.animations.mine, 15, 0)
-	self.object:setvelocity{x = 0, y = 0, z = 0}
+        self.state = state.punch
+        self.object:set_animation(maidroid.animations.mine, 15, 0)
+        self.object:setvelocity{x = 0, y = 0, z = 0}
       elseif pos.x == self.preposition.x or pos.z == self.preposition.z then
-	_aux.change_dir(self)
+        _aux.change_dir(self)
       elseif forward_node.name == "air"
-      and minetest.get_item_group(forward_under_node.name, "soil") > 0
-      and has_sapling_item(self) then
-	self.state = state.plant
-	self.object:set_animation(maidroid.animations.mine, 15, 0)
-	self.object:setvelocity{x = 0, y = 0, z = 0}
-      end
-      -- pickup sapling items
-      _aux.pickup_item(self, 1.5, function(itemstring)
-	return util.table_find_value(target_sapling_list, itemstring) 
-      end)
-      
-    elseif self.state == state.punch then
-      if self.time_count >= max_punch_time then
-	local punch_flag, forward_upper_pos, forward_upper_node
-	  = check_punch_flag(forward_pos)
-	if punch_flag then
-	  minetest.remove_node(forward_upper_pos)
-	  local inv = minetest.get_inventory{type = "detached", name = self.invname}
-	  local stacks = minetest.get_node_drops(forward_upper_node.name)
-	  for _, stack in ipairs(stacks) do
-	    local leftover = inv:add_item("main", stack)
-	    minetest.add_item(forward_pos, leftover)
-	  end
-	end
-	if (not forward_upper_pos) or (forward_upper_pos and
-	  not check_punch_flag(_aux.get_upper_pos(forward_upper_pos))) then
-	  self.state = state.walk
-	  self.object:set_animation(maidroid.animations.walk, 15, 0)
-	  _aux.change_dir(self)
-	end
-	self.time_count = 0
-      else
-	self.time_count = self.time_count + 1
-      end
-      
-    elseif self.state == state.plant then
-      if self.time_count > max_plant_time then
-	if forward_node.name == "air"
-	and minetest.get_item_group(forward_under_node.name, "soil") > 0 then
-	  local inv = minetest.get_inventory{type = "detached", name = self.invname}
-	  local stacks = inv:get_list("main")
-	  for i, stack in ipairs(stacks) do
-	    local itemname = stack:get_name()
-	    if util.table_find_value(target_sapling_list, itemname) then
-	      minetest.add_node(forward_pos, {name = itemname, param2 = 1})
-	      stack:take_item(1)
-	      inv:set_stack("main", i, stack)
-	      break
-	    end
-	  end
-	end
-	self.state = state.walk
-	self.object:set_animation(maidroid.animations.walk, 15, 0)
-	self.time_count = 0
-	_aux.change_dir(self)
-      else
-	self.time_count = self.time_count + 1
+        and minetest.get_item_group(forward_under_node.name, "soil") > 0
+        and has_sapling_item(self) then
+          self.state = state.plant
+          self.object:set_animation(maidroid.animations.mine, 15, 0)
+          self.object:setvelocity{x = 0, y = 0, z = 0}
+        end
+        -- pickup sapling items
+        _aux.pickup_item(self, 1.5, function(itemstring)
+          return util.table_find_value(target_sapling_list, itemstring)
+        end)
+
+      elseif self.state == state.punch then
+        if self.time_count >= max_punch_time then
+          local punch_flag, forward_upper_pos, forward_upper_node
+          = check_punch_flag(forward_pos)
+          if punch_flag then
+            minetest.remove_node(forward_upper_pos)
+            local inv = minetest.get_inventory{type = "detached", name = self.invname}
+            local stacks = minetest.get_node_drops(forward_upper_node.name)
+            for _, stack in ipairs(stacks) do
+              local leftover = inv:add_item("main", stack)
+              minetest.add_item(forward_pos, leftover)
+            end
+          end
+          if (not forward_upper_pos) or (forward_upper_pos and
+          not check_punch_flag(_aux.get_upper_pos(forward_upper_pos))) then
+            self.state = state.walk
+            self.object:set_animation(maidroid.animations.walk, 15, 0)
+            _aux.change_dir(self)
+          end
+          self.time_count = 0
+        else
+          self.time_count = self.time_count + 1
+        end
+
+      elseif self.state == state.plant then
+        if self.time_count > max_plant_time then
+          if forward_node.name == "air"
+          and minetest.get_item_group(forward_under_node.name, "soil") > 0 then
+            local inv = minetest.get_inventory{type = "detached", name = self.invname}
+            local stacks = inv:get_list("main")
+            for i, stack in ipairs(stacks) do
+              local itemname = stack:get_name()
+              if util.table_find_value(target_sapling_list, itemname) then
+                minetest.add_node(forward_pos, {name = itemname, param2 = 1})
+                stack:take_item(1)
+                inv:set_stack("main", i, stack)
+                break
+              end
+            end
+          end
+          self.state = state.walk
+          self.object:set_animation(maidroid.animations.walk, 15, 0)
+          self.time_count = 0
+          _aux.change_dir(self)
+        else
+          self.time_count = self.time_count + 1
+        end
       end
+      self.preposition = pos
     end
-    self.preposition = pos
-  end
-})
+  })