diff --git a/src/constants.py b/src/constants.py
index 61c2cbc..8d57f17 100644
--- a/src/constants.py
+++ b/src/constants.py
@@ -2,7 +2,7 @@
 # See LICENSE file for licensing details.
 
 """File containing constants to be used in the charm."""
- 
+
 import pathlib
 
 # App
@@ -23,7 +23,9 @@
 IRC_BRIDGE_UNIT_FILE_PATH = SYSTEMD_DIR_PATH / "matrix-appservice-irc.service"
 IRC_BRIDGE_TARGET_FILE_PATH = SYSTEMD_DIR_PATH / "matrix-appservice-irc.target"
 IRC_BRIDGE_TEMPLATE_UNIT_FILE_PATH = IRC_BRIDGE_TEMPLATE_DIR_PATH / "matrix-appservice-irc.service"
-IRC_BRIDGE_TEMPLATE_TARGET_FILE_PATH = IRC_BRIDGE_TEMPLATE_DIR_PATH / "matrix-appservice-irc.target"
+IRC_BRIDGE_TEMPLATE_TARGET_FILE_PATH = (
+    IRC_BRIDGE_TEMPLATE_DIR_PATH / "matrix-appservice-irc.target"
+)
 IRC_BRIDGE_PEM_FILE_PATH = IRC_BRIDGE_CONFIG_DIR_PATH / "irc_passkey.pem"
 IRC_BRIDGE_REGISTRATION_FILE_PATH = IRC_BRIDGE_CONFIG_DIR_PATH / "appservice-registration-irc.yaml"
 
diff --git a/src/database_observer.py b/src/database_observer.py
index 94067d4..1424653 100644
--- a/src/database_observer.py
+++ b/src/database_observer.py
@@ -19,7 +19,6 @@ class DatabaseObserver(Object):
     Attributes:
         relation_name: The name of the relation to observe.
         database: The database relation interface.
-        uri: The database uri.
     """
 
     def __init__(self, charm: CharmBase, relation_name: str):
@@ -44,7 +43,11 @@ def _on_database_created(self, _: DatabaseCreatedEvent) -> None:
         self._charm.reconcile()  # type: ignore
 
     def get_db(self) -> typing.Optional[DatasourcePostgreSQL]:
-        """Return a postgresql datasource model."""
+        """Return a postgresql datasource model.
+
+        Returns:
+            DatasourcePostgreSQL: The datasource model.
+        """
         # not using get_relation due this issue
         # https://github.com/canonical/operator/issues/1153
         if not self.model.relations.get(self.database.relation_name):
@@ -52,7 +55,3 @@ def get_db(self) -> typing.Optional[DatasourcePostgreSQL]:
 
         relation = self.model.get_relation(self.relation_name)
         return DatasourcePostgreSQL.from_relation(relation)
-
-        relation_id = self.database.relations[0].id
-        relation_data = self.database.fetch_relation_data(relation_ids=[relation_id])[0]
-
diff --git a/src/irc.py b/src/irc.py
index 1fcbae8..259fbeb 100644
--- a/src/irc.py
+++ b/src/irc.py
@@ -4,7 +4,6 @@
 """IRC Bridge charm business logic."""
 
 import logging
-import pathlib
 import shutil
 import subprocess  # nosec
 
@@ -15,21 +14,21 @@
 import exceptions
 from charm_types import CharmConfig, DatasourceMatrix, DatasourcePostgreSQL
 from constants import (
+    IRC_BRIDGE_CONFIG_DIR_PATH,
+    IRC_BRIDGE_CONFIG_FILE_PATH,
     IRC_BRIDGE_HEALTH_PORT,
     IRC_BRIDGE_KEY_ALGO,
     IRC_BRIDGE_KEY_OPTS,
-    IRC_BRIDGE_CONFIG_DIR_PATH,
-    IRC_BRIDGE_CONFIG_FILE_PATH,
     IRC_BRIDGE_PEM_FILE_PATH,
     IRC_BRIDGE_REGISTRATION_FILE_PATH,
+    IRC_BRIDGE_SNAP_NAME,
+    IRC_BRIDGE_TARGET_FILE_PATH,
     IRC_BRIDGE_TEMPLATE_CONFIG_FILE_PATH,
     IRC_BRIDGE_TEMPLATE_TARGET_FILE_PATH,
     IRC_BRIDGE_TEMPLATE_UNIT_FILE_PATH,
-    IRC_BRIDGE_TARGET_FILE_PATH,
     IRC_BRIDGE_UNIT_FILE_PATH,
-    IRC_BRIDGE_SNAP_NAME,
     SNAP_PACKAGES,
-    SYSTEMD_DIR_PATH
+    SYSTEMD_DIR_PATH,
 )
 
 logger = logging.getLogger(__name__)
@@ -148,8 +147,8 @@ def _generate_pem_file_local(self) -> None:
             "/bin/bash",
             "-c",
             f"[[ -f {IRC_BRIDGE_PEM_FILE_PATH} ]] || "
-            + "openssl genpkey -out {IRC_BRIDGE_PEM_FILE_PATH} "
-            + "-outform PEM -algorithm {IRC_BRIDGE_KEY_ALGO} -pkeyopt {IRC_BRIDGE_KEY_OPTS}",
+            f"openssl genpkey -out {IRC_BRIDGE_PEM_FILE_PATH} "
+            f"-outform PEM -algorithm {IRC_BRIDGE_KEY_ALGO} -pkeyopt {IRC_BRIDGE_KEY_OPTS}",
         ]
         logger.info("Creating PEM file for IRC bridge.")
         subprocess.run(pem_create_command, shell=True, check=True, capture_output=True)  # nosec
diff --git a/tests/unit/test_irc.py b/tests/unit/test_irc.py
index 704c08e..ee5971d 100644
--- a/tests/unit/test_irc.py
+++ b/tests/unit/test_irc.py
@@ -28,8 +28,7 @@
     IRC_BRIDGE_TEMPLATE_CONFIG_FILE_PATH,
     IRC_BRIDGE_TEMPLATE_TARGET_FILE_PATH,
     IRC_BRIDGE_TEMPLATE_UNIT_FILE_PATH,
-    IRC_BRIDGE_TEMPLATE_DIR_PATH,
-    SYSTEMD_DIR_PATH
+    SYSTEMD_DIR_PATH,
 )
 from irc import InstallError, IRCBridgeService, ReloadError, StartError, StopError
 
@@ -268,8 +267,8 @@ def test_configure_generates_pem_file_local(irc_bridge_service, mocker):
             "/bin/bash",
             "-c",
             f"[[ -f {IRC_BRIDGE_PEM_FILE_PATH} ]] || "
-            + "openssl genpkey -out {IRC_BRIDGE_PEM_FILE_PATH} "
-            + "-outform PEM -algorithm {IRC_BRIDGE_KEY_ALGO} -pkeyopt {IRC_BRIDGE_KEY_OPTS}",
+            f"openssl genpkey -out {IRC_BRIDGE_PEM_FILE_PATH} "
+            f"-outform PEM -algorithm {IRC_BRIDGE_KEY_ALGO} -pkeyopt {IRC_BRIDGE_KEY_OPTS}",
         ],
         shell=True,  # nosec
         check=True,