diff --git a/mdit_py_plugins/dollarmath/index.py b/mdit_py_plugins/dollarmath/index.py
index 9c531da..2663617 100644
--- a/mdit_py_plugins/dollarmath/index.py
+++ b/mdit_py_plugins/dollarmath/index.py
@@ -54,7 +54,9 @@ def dollarmath_plugin(
     # would be good to allow "proper" math rendering,
     # e.g. https://github.com/roniemartinez/latex2mathml
 
-    _renderer = lambda content, _: escapeHtml(content) if renderer is None else renderer
+    _renderer = (
+        (lambda content, _: escapeHtml(content)) if renderer is None else renderer
+    )
 
     if label_renderer is None:
         _label_renderer = (
diff --git a/tests/test_dollarmath.py b/tests/test_dollarmath.py
index d10d724..62f52ef 100644
--- a/tests/test_dollarmath.py
+++ b/tests/test_dollarmath.py
@@ -81,6 +81,11 @@ def test_plugin_parse(data_regression):
     data_regression.check([t.as_dict() for t in tokens])
 
 
+def test_custom_renderer(data_regression):
+    md = MarkdownIt().use(dollarmath_plugin, renderer=lambda x, y: x)
+    assert md.render("$x$").strip() == '<p><span class="math inline">x</span></p>'
+
+
 @pytest.mark.parametrize(
     "line,title,input,expected",
     read_fixture_file(FIXTURE_PATH.joinpath("dollar_math.md")),