diff --git a/pyproject.toml b/pyproject.toml
index 34a4b30..8d6083f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,3 +14,6 @@ analyzeUnannotatedFunctions = 'false'
 executionEnvironments = [
   { root = "./" }
 ]
+
+[tool.black]
+line-length=120