Don't set a label if there is none

1 changed files with 3 additions and 2 deletions
--- a/src/convert/init.py
+++ b/src/convert/init.py
@ -138,8 +138,9 @@ class GemParser:
        # This is a pre start tag
        if starts_with_pre and self.mstate != StateEnum.PRETEXT:
            self.mstate = StateEnum.PRETEXT
-            rstring += self.get_start_tag().format(' aria-label="{}"'.format(
-                line[4:].rstrip('\n')))
+            label: str = line[4:].rstrip('\n').strip()
+            rstring += self.get_start_tag().format(
+                ' aria-label="{}"'.format(label) if label else '')
            return rstring
        # This is in pre formatted text
        elif self.mstate == StateEnum.PRETEXT and not starts_with_pre: