1 files changed, 1 insertions, 1 deletions
diff --git a/markdown.py b/markdown.py
index 181de1d..116a974 100644
--- a/markdown.py
+++ b/markdown.py
@@ -1628,7 +1628,7 @@ class Markdown:
         @returns: A serialized XHTML body."""
         #try :
 
-        if source :
+        if source is not None: #Allow blank string
             self.source = source
 
         if not self.source :