diff --git a/Modules/LDAPObject.c b/Modules/LDAPObject.c
index 71fac73e..5b2dad02 100644
--- a/Modules/LDAPObject.c
+++ b/Modules/LDAPObject.c
@@ -288,7 +288,10 @@ attrs_from_List(PyObject *attrlist, char ***attrsp)
         if (seq == NULL)
             goto error;
 
-        len = PySequence_Length(attrlist);
+	len = PySequence_Size(seq);
+	if (len == -1) {
+	    goto error;
+	}
 
         attrs = PyMem_NEW(char *, len + 1);
 
diff --git a/Tests/t_ldapobject.py b/Tests/t_ldapobject.py
index ada5f990..85c29f27 100644
--- a/Tests/t_ldapobject.py
+++ b/Tests/t_ldapobject.py
@@ -474,6 +474,7 @@ def test_dse(self):
             [self.server.suffix.encode('utf-8')]
         )
 
+
     def test_compare_s_true(self):
         base = self.server.suffix
         l = self._ldap_conn
@@ -565,6 +566,38 @@ def test_slapadd(self):
             ("myAttribute", b'foobar'),
         ])
 
+    def test_valid_attrlist_parameter_types(self):
+        """Tests the case when a valid parameter type is passed to search_ext
+
+        Any iterable which only contains strings should not raise any errors.
+        """
+
+        l = self._ldap_conn
+
+        valid_attrlist_parameters = [{"a": "2"}, ["a", "b"], {}, set(), set(["a", "b"])]
+
+        for attrlist in valid_attrlist_parameters:
+            out = l.search_ext(
+                "%s" % self.server.suffix, ldap.SCOPE_SUBTREE, attrlist=attrlist
+            )
+
+    def test_invalid_attrlist_parameter_types(self):
+        """Tests the case when an invalid parameter type is passed to search_ext
+
+        Any object type that is either not a interable or does contain something
+        that isn't a string should raise a TypeError. The exception is the string type itself.
+        """
+
+        invalid_attrlist_parameters = [{1: 2}, 0, object(), "string"]
+
+        l = self._ldap_conn
+
+        for attrlist in invalid_attrlist_parameters:
+            with self.assertRaises(TypeError):
+                l.search_ext(
+                    "%s" % self.server.suffix, ldap.SCOPE_SUBTREE, attrlist=attrlist
+                )
+
 
 class Test01_ReconnectLDAPObject(Test00_SimpleLDAPObject):
     """