diff --git a/poetry.lock b/poetry.lock
index 9c8989b..b23039e 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -575,7 +575,7 @@ dbdrivers = ["aiomysql", "asyncpg"]
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7"
-content-hash = "fb4af0739735ad1230da97320edab72d41278ffa78005116f8119705b998aa10"
+content-hash = "ff0825922451c3ebd311666956adc8987677dc66fe5321565213cd3568ebd9ae"
 
 [metadata.files]
 aiomysql = [
diff --git a/pyproject.toml b/pyproject.toml
index 38278a2..3267f4f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,7 @@ asyncpg = {version = "*", optional = true}
 [tool.poetry.dev-dependencies]
 flake8 = "*"
 isort = "*"
-black = "*"
+black = "^20.8b1"
 pytest = "*"
 pytest-xdist = "*"
 pytest-asyncio = "*"