diff --git a/LdapServer.py b/LdapServer.py
index 4ff5396..39bc043 100644
--- a/LdapServer.py
+++ b/LdapServer.py
@@ -154,8 +154,8 @@ class LdapServerException(BaseException):
 # Helpers
 #
 def parse_datetime(value, to_timezone=None, default_timezone=None):
-	assert to_timezone is None or isinstance(to_timezone, datetime.tzinfo), 'to_timezone must be None or datetime.tzinfo object (not %s)' % type(value)
-	assert default_timezone is None or isinstance(default_timezone, datetime.tzinfo) or isinstance(default_timezone, pytz.tzinfo.DstTzInfo) or isinstance(default_timezone, str), 'default_timezone parameter must be None, a string, a pytz.tzinfo.DstTzInfo or a datetime.tzinfo object (not %s)' % type(from_timezone)
+	assert to_timezone is None or isinstance(to_timezone, datetime.tzinfo), 'to_timezone must be None or datetime.tzinfo object (not %s)' % type(to_timezone)
+	assert default_timezone is None or isinstance(default_timezone, datetime.tzinfo) or isinstance(default_timezone, pytz.tzinfo.DstTzInfo) or isinstance(default_timezone, str), 'default_timezone parameter must be None, a string, a pytz.tzinfo.DstTzInfo or a datetime.tzinfo object (not %s)' % type(default_timezone)
 	date = dateutil.parser.parse(value, dayfirst=False)
 	if not date.tzinfo:
 		if not default_timezone:
@@ -178,7 +178,7 @@ def parse_date(value, to_timezone=None, default_timezone=None):
 def format_datetime(value, from_timezone=None, to_timezone=None):
 	assert isinstance(value, datetime.datetime), 'First parameter must be an datetime.datetime object (not %s)' % type(value)
 	assert from_timezone is None or isinstance(from_timezone, datetime.tzinfo) or isinstance(from_timezone, pytz.tzinfo.DstTzInfo) or isinstance(from_timezone, str), 'from_timezone parameter must be None, a string, a pytz.tzinfo.DstTzInfo or a datetime.tzinfo object (not %s)' % type(from_timezone)
-	assert to_timezone is None or isinstance(to_timezone, datetime.tzinfo), 'to_timezone must be None or datetime.tzinfo object (not %s)' % type(value)
+	assert to_timezone is None or isinstance(to_timezone, datetime.tzinfo), 'to_timezone must be None or datetime.tzinfo object (not %s)' % type(to_timezone)
 	if not value.tzinfo:
 		if not from_timezone:
 			from_timezone = dateutil.tz.tzlocal()