diff --git a/packages/google-cloud-texttospeech/synth.py b/packages/google-cloud-texttospeech/synth.py
index d7c5f05531d8..ae28fac39190 100644
--- a/packages/google-cloud-texttospeech/synth.py
+++ b/packages/google-cloud-texttospeech/synth.py
@@ -42,3 +42,5 @@
 # ----------------------------------------------------------------------------
 templated_files = common.py_library(unit_cov_level=97, cov_level=100)
 s.move(templated_files)
+
+s.shell.run(["nox", "-s", "blacken"], hide_output=False)