diff --git a/satisfactory/__init__.py b/satisfactory/__init__.py
index c76b4ed..9942279 100644
--- a/satisfactory/__init__.py
+++ b/satisfactory/__init__.py
@@ -1,7 +1,7 @@
 import os
 import json
 
-from typing import Dict
+from typing import Dict, Generator
 
 class Cookbook(object):
     __recipes: Dict[str, Dict]
@@ -16,23 +16,23 @@ class Cookbook(object):
                 with open(path, 'r') as src:
                     self.__recipes[name] = json.load(src)
 
-    def __getitem__(self, item: str):
+    def __getitem__(self, item: str) -> Dict[str, Dict]:
         return self.__recipes[item]
 
     def all(self):
         return self.__recipes.keys()
 
-    def recipes(self, name: str) -> dict:
+    def recipes(self, name: str) -> Dict:
         return self.__recipes[name]['recipes']
 
-    def is_component(self, name):
+    def is_component(self, name: str) -> bool:
         return 'component' in self.__recipes[name]['type']
 
-    def components(self):
+    def components(self) -> Generator[Dict, None, None]:
         return (i for i in self.all() if self.is_component(i))
 
-    def is_resource(self, name):
+    def is_resource(self, name: str) -> bool:
         return 'resource' in self.__recipes[name]['type']
 
-    def resources(self):
+    def resources(self) -> Generator[Dict, None, None]:
         return (i for i in self.all() if self.is_resource(i))