refactor code

src/mechanize/form/check_box.cr

@@ -2,10 +2,10 @@ class MechanizeCr::FormContent::CheckBox < MechanizeCr::FormContent::Field
   property :checked
   property :form
 
-  def initialize(node : Node | Myhtml::Node, value : String = node.fetch("value", ""))
+  def initialize(node : Node | Myhtml::Node, value = "")
     @checked = !!node["checked"]
     @form    = form
-    super(node)
+    super(node, value)
   end
 
   def check

src/mechanize/http/agent.cr

@@ -6,8 +6,8 @@ module MechanizeCr
     class Agent
       property :request_headers, :context, :cookies
       property history : Array(MechanizeCr::Page)
-      def initialize(@context : Mechanize | Nil = nil, history = Array(MechanizeCr::Page).new)
-        @history = history
+      def initialize(@context : Mechanize | Nil = nil)
+        @history = Array(MechanizeCr::Page).new
         @request_headers = ::HTTP::Headers.new
         @context = context
         @cookies = Hash(String, ::HTTP::Cookies).new

src/mechanize/node.cr

@@ -6,7 +6,6 @@ class Node < Hash(String,String)
   end
 end
 
-
 # This is a real Node got from html.
 struct Myhtml::Node
   delegate :[], to: attributes