Update app.py

app.py

@@ -23,7 +23,7 @@ xlrd .xlsx .Element_has_iter =True #line:26
 
 def remove_non_printable(value):
     if isinstance(value, str):
-        return ''.join(char for char in value if char.isprintable())
+        return re.sub(r'[^\x20-\x7E]', '', value)
     return value
     
 async def faq ():#line:28