diff --git a/gpg-mailgate.py b/gpg-mailgate.py
index 0b1714e..13e2a38 100755
--- a/gpg-mailgate.py
+++ b/gpg-mailgate.py
@@ -179,7 +179,6 @@ def encrypt_all_payloads_inline( message, gpg_to_cmdline ):
 	return encrypted_payloads
 
 def encrypt_all_payloads_mime( message, gpg_to_cmdline ):
-
 	# Convert a plain text email into PGP/MIME attachment style.  Modeled after enigmail.
 	pgp_ver_part = email.message.Message()
 	pgp_ver_part.set_payload("Version: 1\n")
@@ -230,7 +229,7 @@ def encrypt_payload( payload, gpg_to_cmdline, check_nested = True ):
 	global LOG
 
 	raw_payload = payload.get_payload(decode=True)
-	if check_nested and b"-----BEGIN PGP MESSAGE-----" in raw_payload and b"-----END PGP MESSAGE-----" in raw_payload:
+	if check_nested and text.is_pgp_inline(raw_payload):
 		LOG.debug("Message is already pgp encrypted. No nested encryption needed.")
 		return payload
 
@@ -337,22 +336,16 @@ def get_cert_for_email( to_addr, cert_path ):
 	return None
 
 def sanitize_case_sense( address ):
-
 	if conf.config_item_equals('default', 'mail_case_insensitive', 'yes'):
 		address = address.lower()
 	else:
-		if isinstance(address, str):
-			sep = '@'
-		else:
-			sep = b'@'
-		splitted_address = address.split(sep)
+		splitted_address = address.split('@')
 		if len(splitted_address) > 1:
 			address = splitted_address[0] + sep + splitted_address[1].lower()
 
 	return address
 
 def generate_message_from_payloads( payloads, message = None ):
-
 	if message == None:
 		message = email.mime.multipart.MIMEMultipart(payloads.get_content_subtype())
 
@@ -365,7 +358,6 @@ def generate_message_from_payloads( payloads, message = None ):
 	return message
 
 def get_first_payload( payloads ):
-
 	if payloads.is_multipart():
 		return get_first_payload(payloads.get_payload(0))
 	else:
@@ -376,7 +368,7 @@ def send_msg( message, recipients ):
 
 	recipients = [_f for _f in recipients if _f]
 	if recipients:
-		LOG.info("Sending email to: <%s>" % '> <'.join( recipients ))
+		LOG.info(f"Sending email to: {recipients!r}")
 		relay = (conf.get_item('relay', 'host'), int(conf.get_item('relay', 'port')))
 		smtp = smtplib.SMTP(relay[0], relay[1])
 		if conf.config_item_equals('relay', 'starttls', 'yes'):
@@ -388,9 +380,7 @@ def send_msg( message, recipients ):
 def sort_recipients( raw_message, from_addr, to_addrs ):
 	global LOG
 
-	recipients_left = list()
-	for recipient in to_addrs:
-		recipients_left.append(sanitize_case_sense(recipient))
+	recipients_left = [sanitize_case_sense(recipient) for recipient in to_addrs]
 
 	# There is no need for nested encryption
 	first_payload = get_first_payload(raw_message)
@@ -400,7 +390,7 @@ def sort_recipients( raw_message, from_addr, to_addrs ):
 		return
 
 	first_payload = first_payload.get_payload(decode=True)
-	if b"-----BEGIN PGP MESSAGE-----" in first_payload and b"-----END PGP MESSAGE-----" in first_payload:
+	if text.is_pgp_inline(first_payload):
 		LOG.debug("Message is already encrypted as PGP/INLINE. Encryption aborted.")
 		send_msg(raw_message.as_string(), recipients_left)
 		return
@@ -431,8 +421,8 @@ LOG = logging.getLogger(__name__)
 
 missing_params = conf.validate_config()
 if missing_params:
-    LOG.error(f"Aborting delivery! Following mandatory config parameters are missing: {missing_params!r}")
-    sys.exit(EX_CONFIG)
+	LOG.error(f"Aborting delivery! Following mandatory config parameters are missing: {missing_params!r}")
+	sys.exit(EX_CONFIG)
 
 # Read e-mail from stdin
 raw = sys.stdin.read()
diff --git a/lacre/text.py b/lacre/text.py
index 41f2166..ad85daf 100644
--- a/lacre/text.py
+++ b/lacre/text.py
@@ -1,5 +1,8 @@
 import sys
 
+PGP_INLINE_BEGIN = b"-----BEGIN PGP MESSAGE-----"
+PGP_INLINE_END = b"-----END PGP MESSAGE-----"
+
 def parse_content_type(content_type):
 	split_at = content_type.find(';')
 	if split_at < 0:
@@ -9,3 +12,7 @@ def parse_content_type(content_type):
 		return (content_type[0 : split_at], second_part[second_part.index('=') + 1 : ].strip())
 	else:
 		return (content_type[0 : split_at], sys.getdefaultencoding())
+
+def is_pgp_inline(payload):
+	"""Finds out if the payload (bytes) contains PGP/INLINE markers."""
+	return PGP_INLINE_BEGIN in payload and PGP_INLINE_END in payload