diff --git a/lib/tfw/components/webide_event_handler.py b/lib/tfw/components/webide_event_handler.py
index 0e4f859..1f81f0c 100644
--- a/lib/tfw/components/webide_event_handler.py
+++ b/lib/tfw/components/webide_event_handler.py
@@ -40,9 +40,9 @@ class FileManager:  # pylint: disable=too-many-instance-attributes
     @workdir.setter
     def workdir(self, directory):
         if not exists(directory) or not isdir(directory):
-            raise EnvironmentError('"{}" is not a directory!'.format(directory))
+            raise EnvironmentError(f'"{directory}" is not a directory!')
         if not self._is_in_whitelisted_dir(directory):
-            raise EnvironmentError('Directory "{}" is not in whitelist!'.format(directory))
+            raise EnvironmentError(f'Directory "{directory}" is not in whitelist!')
         self._workdir = directory
 
     @property
diff --git a/lib/tfw/linear_fsm.py b/lib/tfw/linear_fsm.py
index ca73002..274bf52 100644
--- a/lib/tfw/linear_fsm.py
+++ b/lib/tfw/linear_fsm.py
@@ -13,6 +13,6 @@ class LinearFSM(FSMBase):
     """
     def __init__(self, number_of_steps):
         self.states = list(map(str, range(number_of_steps)))
-        self.transitions = [{'trigger': 'step_{}'.format(int(index)+1), 'source': index, 'dest': str(int(index)+1)}
+        self.transitions = [{'trigger': f'step_{int(index)+1}', 'source': index, 'dest': str(int(index)+1)}
                             for index in self.states[:-1]]
         super(LinearFSM, self).__init__()
diff --git a/lib/tfw/networking/controller_connector.py b/lib/tfw/networking/controller_connector.py
index 708c46d..b344ce1 100644
--- a/lib/tfw/networking/controller_connector.py
+++ b/lib/tfw/networking/controller_connector.py
@@ -12,7 +12,7 @@ class ControllerConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(ControllerConnector, self).__init__(zmq_context)
         self._zmq_rep_socket = self._zmq_context.socket(zmq.REP)
-        self._zmq_rep_socket.connect('tcp://localhost:{}'.format(TFWENV.CONTROLLER_PORT))
+        self._zmq_rep_socket.connect(f'tcp://localhost:{TFWENV.CONTROLLER_PORT}')
         self._zmq_rep_stream = ZMQStream(self._zmq_rep_socket)
 
         self.register_callback = self._zmq_rep_stream.on_recv_stream
diff --git a/lib/tfw/networking/event_handlers/server_connector.py b/lib/tfw/networking/event_handlers/server_connector.py
index 5d5f21b..29c89da 100644
--- a/lib/tfw/networking/event_handlers/server_connector.py
+++ b/lib/tfw/networking/event_handlers/server_connector.py
@@ -15,7 +15,7 @@ class ServerDownlinkConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(ServerDownlinkConnector, self).__init__(zmq_context)
         self._zmq_sub_socket = self._zmq_context.socket(zmq.SUB)
-        self._zmq_sub_socket.connect('tcp://localhost:{}'.format(TFWENV.PUBLISHER_PORT))
+        self._zmq_sub_socket.connect(f'tcp://localhost:{TFWENV.PUBLISHER_PORT}')
         self._zmq_sub_stream = ZMQStream(self._zmq_sub_socket)
 
         self.subscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.SUBSCRIBE)
@@ -30,7 +30,7 @@ class ServerUplinkConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(ServerUplinkConnector, self).__init__(zmq_context)
         self._zmq_push_socket = self._zmq_context.socket(zmq.PUSH)
-        self._zmq_push_socket.connect('tcp://localhost:{}'.format(TFWENV.RECEIVER_PORT))
+        self._zmq_push_socket.connect(f'tcp://localhost:{TFWENV.RECEIVER_PORT}')
 
     def send_to_eventhandler(self, message):
         """
diff --git a/lib/tfw/networking/server/event_handler_connector.py b/lib/tfw/networking/server/event_handler_connector.py
index a735673..542bac1 100644
--- a/lib/tfw/networking/server/event_handler_connector.py
+++ b/lib/tfw/networking/server/event_handler_connector.py
@@ -16,7 +16,7 @@ class EventHandlerDownlinkConnector(ZMQConnectorBase):
         super(EventHandlerDownlinkConnector, self).__init__(zmq_context)
         self._zmq_pull_socket = self._zmq_context.socket(zmq.PULL)
         self._zmq_pull_stream = ZMQStream(self._zmq_pull_socket)
-        address = 'tcp://*:{}'.format(TFWENV.RECEIVER_PORT)
+        address = f'tcp://*:{TFWENV.RECEIVER_PORT}'
         self._zmq_pull_socket.bind(address)
         LOG.debug('Pull socket bound to %s', address)
 
@@ -25,7 +25,7 @@ class EventHandlerUplinkConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(EventHandlerUplinkConnector, self).__init__(zmq_context)
         self._zmq_pub_socket = self._zmq_context.socket(zmq.PUB)
-        address = 'tcp://*:{}'.format(TFWENV.PUBLISHER_PORT)
+        address = f'tcp://*:{TFWENV.PUBLISHER_PORT}'
         self._zmq_pub_socket.bind(address)
         LOG.debug('Pub socket bound to %s', address)