diff --git a/telethon/extensions/html.py b/telethon/extensions/html.py
index 869cc96e..ebb67b72 100644
--- a/telethon/extensions/html.py
+++ b/telethon/extensions/html.py
@@ -33,16 +33,20 @@ class HTMLToTelegramParser(HTMLParser):
         attrs = dict(attrs)
         EntityType = None
         args = {}
-        if tag == 'strong' or tag == 'b':
+        if tag in ["strong", "b"]:
             EntityType = MessageEntityBold
-        elif tag == 'em' or tag == 'i':
+        elif tag in ["em", "i"]:
             EntityType = MessageEntityItalic
         elif tag == 'u':
             EntityType = MessageEntityUnderline
-        elif tag == 'del' or tag == 's':
+        elif tag in ["del", "s"]:
             EntityType = MessageEntityStrike
         elif tag == 'blockquote':
             EntityType = MessageEntityBlockquote
+            if 'expandable' in attrs:
+                args["collapsed"] = True
+            else:
+                args["collapsed"] = False
         elif tag == 'code':
             try:
                 # If we're in the middle of a <pre> tag, this <code> tag is