Merge pull request #10 from olcf/bugfix/conditional_removes_line

False conditionals now evaluate to ''

src/velocity/_backends.py

@@ -91,7 +91,7 @@ def _filter_content(cls, image: Image, text: str) -> str:
             if image.satisfies(res.group(2)):
                 text = re_sub(r"(\?\?.*\?\?)", res.group(3).strip(), text)
             else:
-                text = ""
+                text = re_sub(r"(\?\?.*\?\?)", "", text)
 
         # remove comments, newlines, and superfluous white space
         text = re_sub(r">>>.*", "", text)