Allow black's Github action params overriding.
diff --git a/README.md b/README.md
index 2ca76dd6415..7cd4d7f13b2 100644
--- a/README.md
+++ b/README.md
@@ -574,6 +574,7 @@ Multiple contributions by:
 - [Gregory P. Smith](mailto:greg@krypto.org)
 - Gustavo Camargo
 - hauntsaninja
+- [Hadi Alqattan](mailto:alqattanhadizaki@gmail.com)
 - [Heaford](mailto:dan@heaford.com)
 - [Hugo Barrera](mailto::hugo@barrera.io)
 - Hugo van Kemenade
diff --git a/action.yml b/action.yml
index 2ce1c0bf2ef..60bf369a3d8 100644
--- a/action.yml
+++ b/action.yml
@@ -6,4 +6,4 @@ branding:
   icon: "check-circle"
 runs:
   using: "docker"
-  image: "Dockerfile"
+  image: "action/Dockerfile"
diff --git a/Dockerfile b/action/Dockerfile
similarity index 64%
rename from Dockerfile
rename to action/Dockerfile
index a03d23a1078..eb2209940db 100644
--- a/Dockerfile
+++ b/action/Dockerfile
@@ -5,4 +5,6 @@ ENV PYTHONUNBUFFERED 1
 
 RUN pip install --upgrade --no-cache-dir black
 
-ENTRYPOINT /usr/local/bin/black --check --diff  .
+COPY entrypoint.sh /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]
diff --git a/action/entrypoint.sh b/action/entrypoint.sh
new file mode 100755
index 00000000000..dc86fa1996e
--- /dev/null
+++ b/action/entrypoint.sh
@@ -0,0 +1,10 @@
+#!/bin/sh
+set -e
+
+if [ $# -eq 0 ]; then
+    # Default (if no args provided).
+    sh -c "black . --check --diff"
+else
+    # Custom args.
+    sh -c "black $*"
+fi
diff --git a/docs/authors.md b/docs/authors.md
index a5349b4b9df..ebf64eaae76 100644
--- a/docs/authors.md
+++ b/docs/authors.md
@@ -69,6 +69,7 @@ Multiple contributions by:
 - [Gregory P. Smith](mailto:greg@krypto.org)
 - Gustavo Camargo
 - hauntsaninja
+- [Hadi Alqattan](mailto:alqattanhadizaki@gmail.com)
 - [Heaford](mailto:dan@heaford.com)
 - [Hugo Barrera](mailto::hugo@barrera.io)
 - Hugo van Kemenade
diff --git a/docs/github_actions.md b/docs/github_actions.md
index 7ff87540242..ac80c2fab6f 100644
--- a/docs/github_actions.md
+++ b/docs/github_actions.md
@@ -15,5 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
-      - uses: psf/black@stable
+      - uses: psf/black@stable # the default is equivalent to `black . --diff --check`.
+        with: # (optional - override the default parameters).
+          args: ". --diff --check"
 ```

Fix: #1751 