diff --git a/pyproject.toml b/pyproject.toml
index b5c2a6b1..284da2ba 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,7 +30,7 @@ pyyaml = "^5.1"
 behave = "^1.2"
 mkdocs = "^1.0"
 flake8 = "^3.7"
-black = {version = "^19.10b0",allows-prereleases = true}
+black = {version = "^19.10b0",allow-prereleases = true}
 
 [tool.poetry.scripts]
 jrnl = 'jrnl.cli:run'