diff --git a/.github/workflows/pre-commit.yml b/.github/workflows/pre-commit.yml
new file mode 100644
index 000000000..7002d2d0a
--- /dev/null
+++ b/.github/workflows/pre-commit.yml
@@ -0,0 +1,15 @@
+name: pre-commit
+
+on: [push, pull_request]
+
+jobs:
+  pre-commit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - name: Install pre-commit
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install --upgrade pre-commit
+      - run: pre-commit run --verbose --all-files --show-diff-on-failure
diff --git a/machine_learning/scoring_functions.py b/machine_learning/scoring_functions.py
old mode 100755
new mode 100644
diff --git a/maths/sum_of_arithmetic_series.py b/maths/sum_of_arithmetic_series.py
old mode 100755
new mode 100644
diff --git a/scheduling/round_robin.py b/scheduling/round_robin.py
old mode 100755
new mode 100644
diff --git a/web_programming/instagram_crawler.py b/web_programming/instagram_crawler.py
index 38e383648..c81635bd3 100644
--- a/web_programming/instagram_crawler.py
+++ b/web_programming/instagram_crawler.py
@@ -15,7 +15,7 @@ def extract_user_profile(script) -> dict:
     May raise json.decoder.JSONDecodeError
     """
     data = script.contents[0]
-    info = json.loads(data[data.find('{"config"'): -1])
+    info = json.loads(data[data.find('{"config"') : -1])
     return info["entry_data"]["ProfilePage"][0]["graphql"]["user"]