diff --git a/libp2p/host/basic_host.py b/libp2p/host/basic_host.py
index 48c322b..253394e 100644
--- a/libp2p/host/basic_host.py
+++ b/libp2p/host/basic_host.py
@@ -3,7 +3,7 @@ from typing import TYPE_CHECKING, List, Sequence
 
 import multiaddr
 
-from libp2p.crypto.keys import PublicKey
+from libp2p.crypto.keys import PrivateKey, PublicKey
 from libp2p.host.defaults import get_default_protocols
 from libp2p.host.exceptions import StreamFailure
 from libp2p.network.network_interface import INetwork
@@ -67,7 +67,7 @@ class BasicHost(IHost):
     def get_public_key(self) -> PublicKey:
         return self.peerstore.pubkey(self.get_id())
 
-    def get_private_key(self) -> PublicKey:
+    def get_private_key(self) -> PrivateKey:
         return self.peerstore.privkey(self.get_id())
 
     def get_network(self) -> INetwork:
diff --git a/libp2p/host/host_interface.py b/libp2p/host/host_interface.py
index 5e28fda..43f4ac4 100644
--- a/libp2p/host/host_interface.py
+++ b/libp2p/host/host_interface.py
@@ -3,7 +3,7 @@ from typing import Any, List, Sequence
 
 import multiaddr
 
-from libp2p.crypto.keys import PublicKey
+from libp2p.crypto.keys import PrivateKey, PublicKey
 from libp2p.network.network_interface import INetwork
 from libp2p.network.stream.net_stream_interface import INetStream
 from libp2p.peer.id import ID
@@ -25,7 +25,7 @@ class IHost(ABC):
         """
 
     @abstractmethod
-    def get_private_key(self) -> PublicKey:
+    def get_private_key(self) -> PrivateKey:
         """
         :return: the private key belonging to the peer
         """
diff --git a/libp2p/peer/peerstore.py b/libp2p/peer/peerstore.py
index 7dc367f..4cff54e 100644
--- a/libp2p/peer/peerstore.py
+++ b/libp2p/peer/peerstore.py
@@ -1,4 +1,4 @@
-from typing import Any, Dict, List, Optional, Sequence, Tuple
+from typing import Any, Dict, List, Optional, Sequence, Set
 
 from multiaddr import Multiaddr
 
@@ -24,7 +24,8 @@ class PeerStore(IPeerStore):
     def __create_or_get_peer(self, peer_id: ID) -> PeerData:
         """
         Returns the peer data for peer_id or creates a new peer data (and
-        stores it in peer_data_map) if peer data for peer_id does not yet exist.
+        stores it in peer_data_map) if peer data for peer_id does not yet
+        exist.
 
         :param peer_id: peer ID
         :return: peer data
@@ -158,7 +159,9 @@ class PeerStore(IPeerStore):
         :raise PeerStoreError: if peer ID already has pubkey set
         """
         if peer_id in self.peer_pubkey_map:
-            raise PeerStoreError(f"peer ID already has pubkey: {self.peer_pubkey_map[peer_id]}")
+            raise PeerStoreError(
+                f"peer ID already has pubkey: {self.peer_pubkey_map[peer_id]}"
+            )
         self.peer_pubkey_map[peer_id] = pubkey
 
     def pubkey(self, peer_id: ID) -> PublicKey:
@@ -178,7 +181,9 @@ class PeerStore(IPeerStore):
         :raise PeerStoreError: if peer ID already has privkey set
         """
         if peer_id in self.peer_privkey_map:
-            raise PeerStoreError(f"peer ID already has privkey: {self.peer_privkey_map[peer_id]}")
+            raise PeerStoreError(
+                f"peer ID already has privkey: {self.peer_privkey_map[peer_id]}"
+            )
         self.peer_privkey_map[peer_id] = privkey
 
     def privkey(self, peer_id: ID) -> PrivateKey:
@@ -191,7 +196,7 @@ class PeerStore(IPeerStore):
             return self.peer_privkey_map[peer_id]
         raise PeerStoreError("peer ID not found")
 
-    def peers_with_keys(self) -> Tuple[ID]:
+    def peers_with_keys(self) -> Set[ID]:
         """
         :return: all of the peer IDs which has pubkey/privkey stored in peer store
         """
diff --git a/libp2p/peer/peerstore_interface.py b/libp2p/peer/peerstore_interface.py
index fbd1a2e..8ebe1cc 100644
--- a/libp2p/peer/peerstore_interface.py
+++ b/libp2p/peer/peerstore_interface.py
@@ -1,5 +1,5 @@
 from abc import abstractmethod
-from typing import Any, List, Sequence, Tuple
+from typing import Any, List, Sequence, Set
 
 from multiaddr import Multiaddr
 
@@ -132,7 +132,7 @@ class IPeerStore(IAddrBook, IPeerMetadata):
         """
 
     @abstractmethod
-    def peers_with_keys(self) -> Tuple[ID]:
+    def peers_with_keys(self) -> Set[ID]:
         """
         :return: all of the peer IDs which has pubkey/privkey stored in peer store
         """
diff --git a/libp2p/tools/factories.py b/libp2p/tools/factories.py
index 341d691..405e6ed 100644
--- a/libp2p/tools/factories.py
+++ b/libp2p/tools/factories.py
@@ -34,7 +34,7 @@ from .constants import (
 from .utils import connect, connect_swarm
 
 
-def initialize_peerstore_with_our_keypair(self_id: ID, key_pair: KeyPair):
+def initialize_peerstore_with_our_keypair(self_id: ID, key_pair: KeyPair) -> PeerStore:
     peer_store = PeerStore()
     peer_store.add_pubkey(self_id, key_pair.public_key)
     peer_store.add_privkey(self_id, key_pair.private_key)