Improve a bit ppt support

libmat2/office.py

@@ -307,7 +307,8 @@ class MSOfficeParser(ZipParser):
             # so we're removing as much as we can.
             with open(full_path, 'wb') as f:
                 f.write(b'<?xml version="1.0">')
-                f.write(b'<a:tblStyleLst def="{%s}" xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main"/>' % str(uuid.uuid4()).encode('utf-8'))
+                uid = str(uuid.uuid4()).encode('utf-8')
+                f.write(b'<a:tblStyleLst def="{%s}" xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main"/>' % uid)
 
         if self.__remove_rsid(full_path) is False:
             return False