Fixed fetch call

lib/memo_wise.rb

@@ -107,38 +107,20 @@ def #{method_name}
       memo_wise_module.module_eval <<~HEREDOC, __FILE__, __LINE__ + 1
         def #{method_name}(#{MemoWise::InternalAPI.args_str(method)})
           _memo_wise_hash = (_memo_wise[:#{method_name}] ||= {})
-          _memo_wise_output = _memo_wise_hash[#{key}]
-          if _memo_wise_output || _memo_wise_hash.key?(#{key})
-            _memo_wise_output
-          else
+          _memo_wise_hash.fetch(#{key}) do
             _memo_wise_hash[#{key}] = super
           end
         end
       HEREDOC
       # MemoWise::InternalAPI::MULTIPLE_REQUIRED, MemoWise::InternalAPI::SPLAT,
       # MemoWise::InternalAPI::DOUBLE_SPLAT, MemoWise::InternalAPI::SPLAT_AND_DOUBLE_SPLAT
     else
-      # NOTE: When benchmarking this implementation against something like:
-      #
-      #   @_memo_wise.fetch(key) do
-      #     ...
-      #   end
-      #
-      # this implementation may sometimes perform worse than the above. This
-      # is because this case uses a more complex hash key (see
-      # `MemoWise::InternalAPI.key_str`), and hashing that key has less
-      # consistent performance. In general, this should still be faster for
-      # truthy results because `Hash#[]` generally performs hash lookups
-      # faster than `Hash#fetch`.
       memo_wise_module.module_eval <<~HEREDOC, __FILE__, __LINE__ + 1
         def #{method_name}(#{MemoWise::InternalAPI.args_str(method)})
           _memo_wise_hash = (_memo_wise[:#{method_name}] ||= {})
           _memo_wise_key = #{MemoWise::InternalAPI.key_str(method)}
 
-          _memo_wise_output = _memo_wise_hash[_memo_wise_key]
-          if _memo_wise_output || _memo_wise_hash.key?(_memo_wise_key)
-            _memo_wise_output
-          else
+          _memo_wise_hash.fetch(_memo_wise_key) do
             _memo_wise_hash[_memo_wise_key] = super
           end
         end