diff --git a/striplog/component.py b/striplog/component.py
index <HASH>..<HASH> 100644
--- a/striplog/component.py
+++ b/striplog/component.py
@@ -228,7 +228,7 @@ class Component(object):
         if fmt == '':
             return default
 
-        keys = [k for k, v in self.__dict__.items() if v is not '']
+        keys = [k for k, v in self.__dict__.items() if v != '']
 
         f = fmt or '{' + '}, {'.join(keys) + '}'
Changing to "!=" with literal avoids SyntaxWarning (#<I>)

Previously the following warning was raised when importing striplog:

`component.py:<I>: SyntaxWarning: "is not" with a literal.

Did you mean "!="?`



This change simply follows the suggested fix to avoid that warning.