diff --git a/lib/helper.rb b/lib/helper.rb
index 868b68c..cedc76b 100644
--- a/lib/helper.rb
+++ b/lib/helper.rb
@@ -18,16 +18,30 @@ def generate_storage_key_from_metadata(metadata, module_name, storage_name, para
         return_type = map[:value]
         # TODO: decode to account id if param is address
         # params[0] = decode(params[0]) if map[:key] == "AccountId"
+
         type = Scale::Types.get(map[:key])
-        params[0] = type.new(params[0]).encode
+        if params[0].class != type
+          raise Scale::StorageInputTypeError.new("The type of first param is not equal to the type from metadata: #{map[:key]} => #{type}")
+        end
+        params[0] = params[0].encode
       elsif map = storage_item[:type][:DoubleMap]
         raise "Storage call of type \"DoubleMapType\" requires 2 parameters" if params.nil? || params.length != 2
 
         hasher = map[:hasher]
         hasher2 = map[:key2Hasher]
         return_type = map[:value]
-        params[0] = Scale::Types.get(map[:key1]).new(params[0]).encode
-        params[1] = Scale::Types.get(map[:key2]).new(params[1]).encode
+
+        type1 = Scale::Types.get(map[:key1])
+        if params[0].class != type1
+          raise Scale::StorageInputTypeError.new("The type of 1st param is not equal to the type from metadata: #{map[:key1]} => #{type1.class.name}")
+        end
+        params[0] = params[0].encode
+
+        type2 = Scale::Types.get(map[:key2])
+        if params[1].class != type2
+          raise Scale::StorageInputTypeError.new("The type of 2nd param is not equal to the type from metadata: #{map[:key2]} => #{type2.class.name}")
+        end
+        params[1] = params[1].encode
       else
         raise NotImplementedError
       end
diff --git a/lib/scale.rb b/lib/scale.rb
index ef44005..a9d33e5 100644
--- a/lib/scale.rb
+++ b/lib/scale.rb
@@ -39,6 +39,7 @@ class ScaleError < StandardError; end
   class TypeBuildError < ScaleError; end
   class BadDataError < ScaleError; end
   class TypeRegistryNotLoadYet < ScaleError; end
+  class StorageInputTypeError < ScaleError; end
 
   module Types
     class << self
diff --git a/spec/substrate_client_spec.rb b/spec/substrate_client_spec.rb
index 2f0f548..92d80b4 100644
--- a/spec/substrate_client_spec.rb
+++ b/spec/substrate_client_spec.rb
@@ -114,13 +114,14 @@
     expect(size).to be_instance_of Integer
   end
 
-  it "can call state_getKeys" do
-    keys = @client.state_getKeys("0x26aa394eea5630e07c48ae0c9558cef7") # System
-    expect(keys).to be_instance_of Array
+  # Too time consuming
+  # it "can call state_getKeys" do
+  #   keys = @client.state_getKeys("0x26aa394eea5630e07c48ae0c9558cef7") # System
+  #   expect(keys).to be_instance_of Array
 
-    keys = @client.state_getKeys("0x26aa394eea5630e07c48ae0c9558cef7", "0x860e0ed04bd1b2a1efa70c9db13cc73f830d7e14204680316db52f05fd91ba37") # System
-    expect(keys.length).to eq(24860)
-  end
+  #   keys = @client.state_getKeys("0x26aa394eea5630e07c48ae0c9558cef7", "0x860e0ed04bd1b2a1efa70c9db13cc73f830d7e14204680316db52f05fd91ba37") # System
+  #   expect(keys.length).to eq(24860)
+  # end
 
   it "can call state_getReadProof" do
     read_proof = @client.state_getReadProof(["0x26aa394eea5630e07c48ae0c9558cef780d41e5e16056765bc8461851072c9d7"], "0x860e0ed04bd1b2a1efa70c9db13cc73f830d7e14204680316db52f05fd91ba37")
@@ -170,7 +171,8 @@
   end
 
   it "can get decoded storage" do 
-    account = @client.get_storage "System", "Account", ["0x50be873393f9e3f5705d8b573729cd35b080e5f9029534e8b848371a9cdecc1e"], "0xedf6ff93fb6dd1c00b96dafb576e01975e85710ff3b0eea7244e576579f28388"
+    account_id = Scale::Types::AccountId.new("0x50be873393f9e3f5705d8b573729cd35b080e5f9029534e8b848371a9cdecc1e")
+    account = @client.get_storage "System", "Account", [account_id], "0xedf6ff93fb6dd1c00b96dafb576e01975e85710ff3b0eea7244e576579f28388"
 
     expect_result = {"c"=>2, "data"=>{"feeFrozen"=>499192308000, "free"=>378566339746251, "miscFrozen"=>499192308000, "reserved"=>0}, "nonce"=>0}
     expect(account.to_human).to eq(expect_result)