pyderasn.py | 2 ++

diff --git a/pyderasn.py b/pyderasn.py
index a8b907ea1cc4ceff7c3675a5a898dfa25d6f29783fda0a4da8fc03678d10cba8..0b05723e0089e56bea0ea3abdad0153aaf6822d426a6493c20a2311ad5b5ac60 100755
--- a/pyderasn.py
+++ b/pyderasn.py
@@ -3642,6 +3642,8 @@
     >>> tbs = TBSCertificate()
     >>> tbs["version"] = Version("v2") # no need to explicitly add ``expl``
 
+    Assign ``None`` to remove value from sequence.
+
     You can know if value exists/set in the sequence and take its value:
 
     >>> "extnID" in ext, "extnValue" in ext, "critical" in ext