diff --git a/activate/activate_manager.py b/activate/activate_manager.py
index 622fee6..f8567aa 100644
--- a/activate/activate_manager.py
+++ b/activate/activate_manager.py
@@ -1,29 +1,42 @@
+import functools
 from typing import Callable
 
+from fastapi import HTTPException
+
 from activate.types.activity_streams.core_types import Activity
 
+activate_manager: "ActivateManager"
+
 
 def get_activate_manager():
-    return ActivateManager()
+    global activate_manager
+    if not activate_manager:
+        activate_manager = ActivateManager()
+    return activate_manager
 
 
 class ActivateManager:
-    schema: dict[Activity, Callable]
+    schema: dict[str, Callable] = {}
 
-    def resolve(self, activity: Activity):
+    async def resolve(self, activity: str):
         """
         Called by the web adapter to resolve activities
         """
-        # TODO: check the schema for a registered activity that matches the requested one
-        # TODO: if so, call it
+        if self.schema[Activity]:
+            return await self.schema[Activity](activity)
+        else:
+            raise HTTPException(status_code=404, detail="Activity can NOT be handled")
 
-    def resolver(self):
+    def resolver(self, resolver_function):
         """
         A decorator used by the package user to register custom resolvers for activities
         """
-        def wrapper(resolver_function):
-            # TODO: check that the first argument to the function is an activity
-            # TODO: if so, register the resolver function in schema
-            return resolver_function
+        @functools.wraps(resolver_function)
+        async def wrapper(activity: Activity):
+            self.schema[Activity] = resolver_function
+            return resolver_function(activity)
 
         return wrapper
+
+
+activate_manager = ActivateManager()
diff --git a/activate/types/activity_streams/activity_types.py b/activate/types/activity_streams/activity_types.py
index 47423a5..f995484 100644
--- a/activate/types/activity_streams/activity_types.py
+++ b/activate/types/activity_streams/activity_types.py
@@ -2,11 +2,12 @@
 
 from pydantic import AnyUrl
 
+
 from activate.types.activity_streams.core_types import (
     Activity,
     IntransitiveActivity,
     Object,
-    Link
+    Link,
 )
 
 
@@ -26,7 +27,11 @@ class Arrive(Activity):
     type: AnyUrl = "Arrive"
 
 
-class Block("Ignore"):
+class Ignore(Activity):
+    type: AnyUrl = "Ignore"
+
+
+class Block(Ignore):
     type: AnyUrl = "Block"
 
 
@@ -50,11 +55,11 @@ class Follow(Activity):
     type: AnyUrl = "Follow"
 
 
-class Ignore(Activity):
-    type: AnyUrl = "Ignore"
+class Offer(Activity):
+    type: AnyUrl = "Offer"
 
 
-class Invite("Offer"):
+class Invite(Offer):
     type: AnyUrl = "Invite"
 
 
@@ -68,63 +73,59 @@ class Leave(Activity):
 
 class Like(Activity):
     type: AnyUrl = "Like"
-    
-    
+
+
 class Listen(Activity):
     type: AnyUrl = "Listen"
-    
-    
+
+
 class Move(Activity):
     type: AnyUrl = "Move"
-    
-    
-class Offer(Activity):
-    type: AnyUrl = "Offer"
-    
-    
+
+
 class Question(IntransitiveActivity):
     type: AnyUrl = "Question"
 
     # oneOf and anyOf must NOT exist together
-    #FIXME: how to validate this?
-    oneOf: list[Object | Link] | Object | Link
-    anyOf: list[Object | Link] | Object | Link
+    # FIXME: how to validate this?
+    # oneOf: list[Object | Link] | Object | Link
+    # anyOf: list[Object | Link] | Object | Link
 
     # closed can also be a generic object as per the vocabulary. HOW?
-    closed: datetime | bool
-    
-    
+    # closed: datetime | bool
+
+
 class Reject(Activity):
     type: AnyUrl = "Reject"
-    
-    
+
+
 class Read(Activity):
     type: AnyUrl = "Read"
-    
-    
+
+
 class Remove(Activity):
     type: AnyUrl = "Remove"
-    
-    
+
+
 class TentativeReject(Reject):
     type: AnyUrl = "TentativeReject"
-    
-    
+
+
 class TentativeAccept(Accept):
     type: AnyUrl = "TentativeAccept"
-    
-  
+
+
 class Travel(IntransitiveActivity):
-    type: AnyUrl = "Travel"  
-    
-    
+    type: AnyUrl = "Travel"
+
+
 class Undo(Activity):
     type: AnyUrl = "Undo"
-    
-    
+
+
 class Update(Activity):
     type: AnyUrl = "Update"
-    
-    
+
+
 class View(Activity):
     type: AnyUrl = "View"
diff --git a/activate/types/activity_streams/core_types.py b/activate/types/activity_streams/core_types.py
index df69ad1..0deb316 100644
--- a/activate/types/activity_streams/core_types.py
+++ b/activate/types/activity_streams/core_types.py
@@ -1,8 +1,11 @@
 from datetime import datetime, timedelta
 
+from typing import Union
+
 from pydantic import BaseModel, AnyUrl
 from pydantic import Field
 
+
 class Link(BaseModel):
     # Type is NOT explicitly defined in the standard vocabulary as functional.
     # It is assumed to be functional (a single value) here
@@ -17,7 +20,7 @@ class Link(BaseModel):
     # In the [HTML5], any string NOT containing the
     # "space" U+0020, "tab" (U+0009), "LF" (U+000A), "FF" (U+000C), "CR" (U+000D) or "," (U+002C) characters
     # can be used as a valid link relation.
-    rel: list[str] | str
+    # rel: list[str] | str
 
     # should be a MIME media type (how to validate this? Is there a specific set of MIME types?)
     mediaType: str
@@ -37,7 +40,7 @@ class Link(BaseModel):
     height: int = Field(ge=0)
     width: int = Field(ge=0)
 
-    preview: list["Object" | "Link"] | "Object" | "Link"
+    preview: Union[list["Object"], list["Link"], "Object", "Link"]
 
 
 class Object(BaseModel):
@@ -47,9 +50,9 @@ class Object(BaseModel):
 
     id: AnyUrl | None
 
-    attachment: list["Object" | Link] | "Object" | Link
-    attributedTo: list["Object" | Link] | "Object" | Link
-    audience: list["Object" | Link] | "Object" | Link
+    # attachment: Union[list["Object"], Link, "Object", Link]
+    # attributedTo: Union[list["Object"], Link, "Object", Link]
+    # audience: Union[list["Object" | Link], "Object", Link]
 
     # By default, content is an HTML string.
     # Otherwise, use the mediatype property to declare the type of string. How to enforce this?
@@ -60,7 +63,7 @@ class Object(BaseModel):
 
     # content is NOT explicitly defined in the standard vocabulary as functional.
     # It is assumed to be functional (a single value) here
-    context: "Object" | Link
+    # context: Union["Object", Link]
 
     # name must NOT include HTML markup (how to enforce this?).
     # It can be a map of the name in different languages (maybe a map would be supported later)
@@ -72,16 +75,16 @@ class Object(BaseModel):
 
     # content is NOT explicitly defined in the standard vocabulary as functional.
     # It is assumed to be functional (a single value) here
-    generator: "Object" | Link
+    # generator: Union["Object", Link]
 
     # Icons should be of 1:1 aspect ratio and should be suitable for presentation at a small size
-    icon: list["Image" | Link] | "Image" | Link
+    # icon: Union[list["Image", Link], "Image", Link]
     # Images don't have the limitations assumed in icons
-    image: list["Image" | Link] | "Image" | Link
+    # image: list["Image" | Link] | "Image" | Link
 
-    inReplyTo: list["Object" | Link] | "Object" | Link
-    location: list["Object" | Link] | "Object" | Link
-    preview: list["Object" | Link] | "Object" | Link
+    # inReplyTo: list["Object" | Link] | "Object" | Link
+    # location: list["Object" | Link] | "Object" | Link
+    # preview: list["Object" | Link] | "Object" | Link
     published: datetime
 
     # replies is a collection, but it is a functional property (a single collection)
@@ -90,17 +93,17 @@ class Object(BaseModel):
     startTime: datetime
 
     # Like the content property
-    summary: list[str] | str
+    # summary: list[str] | str
 
     # Attachments imply association by inclusion. Tags imply association by reference.
-    tag: list["Object" | Link] | "Object" | Link
+    # tag: list["Object" | Link] | "Object" | Link
 
     updated: datetime
-    url: list["AnyUrl" | Link] | "AnyUrl" | Link
-    to: list["Object" | Link] | "Object" | Link
-    bto: list["Object" | Link] | "Object" | Link
-    cc: list["Object" | Link] | "Object" | Link
-    bcc: list["Object" | Link] | "Object" | Link
+    # url: list["AnyUrl" | Link] | "AnyUrl" | Link
+    # to: list["Object" | Link] | "Object" | Link
+    # bto: list["Object" | Link] | "Object" | Link
+    # cc: list["Object" | Link] | "Object" | Link
+    # bcc: list["Object" | Link] | "Object" | Link
 
     # should be a MIME media type (how to validate this? Is there a specific set of MIME types?)
     mediaType: str
@@ -112,16 +115,17 @@ class Object(BaseModel):
 
 
 class BaseActivity(Object):
+    ...
     # Abstract class for the activity and IntransitiveActivity Types
 
     # Subproperty of "attributedTO"
-    #TODO: what are the complications of this?
-    actor: list["Object" | Link] | "Object" | Link
+    # TODO: what are the complications of this?
+    # actor: list["Object" | Link] | "Object" | Link
 
-    target: list["Object" | Link] | "Object" | Link
-    result: list["Object" | Link] | "Object" | Link
-    origin: list["Object" | Link] | "Object" | Link
-    instrument: list["Object" | Link] | "Object" | Link
+    # target: list["Object" | Link] | "Object" | Link
+    # result: list["Object" | Link] | "Object" | Link
+    # origin: list["Object" | Link] | "Object" | Link
+    # instrument: list["Object" | Link] | "Object" | Link
 
 
 class IntransitiveActivity(BaseActivity):
@@ -131,7 +135,7 @@ class IntransitiveActivity(BaseActivity):
 class Activity(BaseActivity):
     type: AnyUrl = "Activity"
 
-    object: list["Object" | Link] | "Object" | Link
+    # object: list["Object" | Link] | "Object" | Link
 
 
 class Collection(Object):
@@ -141,10 +145,10 @@ class Collection(Object):
     # serialized within the Collection object instance
     totalItems: int = Field(ge=0)
 
-    current: "CollectionPage" | Link
-    first: "CollectionPage" | Link
-    last: "CollectionPage" | Link
-    items: list[Object | Link] | Object | Link
+    # current: "CollectionPage" | Link
+    # first: "CollectionPage" | Link
+    # last: "CollectionPage" | Link
+    # items: list[Object | Link] | Object | Link
 
 
 class OrderedCollection(Collection):
@@ -154,17 +158,12 @@ class OrderedCollection(Collection):
 class CollectionPage(Collection):
     type: AnyUrl = "CollectionPage"
 
-    partOf: Collection | Link
-    next: "CollectionPage" | Link
-    prev: "CollectionPage" | Link
+    # partOf: Collection | Link
+    # next: "CollectionPage" | Link
+    # prev: "CollectionPage" | Link
 
 
 class OrderedCollectionPage(OrderedCollection, CollectionPage):
     type: AnyUrl = "OrderedCollectionPage"
 
     startIndex: int = Field(ge=0)
-
-
-
-
-
diff --git a/activate/types/activity_streams/extended_object_types.py b/activate/types/activity_streams/extended_object_types.py
index be1be4b..cc8e1f3 100644
--- a/activate/types/activity_streams/extended_object_types.py
+++ b/activate/types/activity_streams/extended_object_types.py
@@ -15,24 +15,27 @@ class Relationship(Object):
     object: Object | Link
 
     relationship: Object
-    
+
 
 class Article(Object):
     type: AnyUrl = "Article"
-    
-    
+
+
 class Document(Object):
     type: AnyUrl = "Document"
-    
-    
+
+
 class Audio(Document):
     type: AnyUrl = "Audio"
-    
-    
+
+
 class Video(Document):
     type: AnyUrl = "Video"
-    
-    
+
+
+class Image(Document):
+    type: AnyUrl = "Video"
+
 class Note(Object):
     type: AnyUrl = "Note"
 
@@ -41,9 +44,10 @@ class Page(Document):
     """
     Represents a web page
     """
+
     type: AnyUrl = "Page"
-    
-    
+
+
 class Event(Object):
     type: AnyUrl = "Event"
 
@@ -61,12 +65,13 @@ class Place(Object):
     # By default it is meters.
     # How to validate it is a unit?
     units: str = "m"
-    
+
 
 class Mention(Link):
     """
     A specialized Link that represents an @mention.
     """
+
     type: AnyUrl = "Mention"
 
 
@@ -82,6 +87,7 @@ class Tombstone(Object):
     It can be used in Collections to signify that
     there used to be an object at this position, but it has been deleted.
     """
+
     type: AnyUrl = "Tombstone"
 
     formerType: Object
diff --git a/activate/web/fastapi/app.py b/activate/web/fastapi/app.py
index c937011..29e59f0 100644
--- a/activate/web/fastapi/app.py
+++ b/activate/web/fastapi/app.py
@@ -9,13 +9,18 @@
 # TODO: check the initialization of the activate manager
 # TODO: check the middleware to ensure the right content-type and accept header are correct
 
+
 @activate_router.get("/")
-async def activitypub_get_endpoint(activity: Activity = Body(),
-                                   activate_manager: ActivateManager = Depends(get_activate_manager)):
+async def activitypub_get_endpoint(
+    activity: Activity = Body(),
+    activate_manager: ActivateManager = Depends(get_activate_manager),
+):
     return await activate_manager.resolve(activity)
 
 
 @activate_router.post("/")
-async def activitypub_post_endpoint(activity: Activity,
-                                    activate_manager: ActivateManager = Depends(get_activate_manager)):
+async def activitypub_post_endpoint(
+    activity: Activity,
+    activate_manager: ActivateManager = Depends(get_activate_manager),
+):
     return await activate_manager.resolve(activity)
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..d68c6e3
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,5 @@
+fastapi==0.91.0
+pytest==7.2.1
+black==23.1.0
+isort==5.12.0
+mypy==1.0.0
\ No newline at end of file
diff --git a/tests/test_reciever.py b/tests/test_reciever.py
new file mode 100644
index 0000000..b4ababf
--- /dev/null
+++ b/tests/test_reciever.py
@@ -0,0 +1,16 @@
+from activate.activate_manager import get_activate_manager
+import pytest
+
+
+@pytest.fixture
+def manager():
+    yield get_activate_manager()
+
+
+def test_manager_resolver(manager):
+    @manager.resolver
+    def to_be_decorated():
+        return "BUG!"
+
+    to_be_decorated("test")
+    assert manager.schema.get("test") is not None