diff --git a/sphinx_d2lang/d2lang.py b/sphinx_d2lang/d2lang.py
index 73c7359..f2c11b7 100644
--- a/sphinx_d2lang/d2lang.py
+++ b/sphinx_d2lang/d2lang.py
@@ -19,7 +19,7 @@ class D2langDirective(Directive):
             for line in self.content:
                 fp.write(bytes(line,'utf-8'))
             cmd_line = '%s %s %s' % (d2_bin, fp.name, srcdir + "/test.svg")
-        args = shlex.split(cmd_line)
-        subprocess.run(args)
+            args = shlex.split(cmd_line)
+            subprocess.run(args)
         image_node = nodes.image(uri="/test.svg")
         return [image_node]