diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..a00cee1
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,18 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-added-large-files
+
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.3.0
+    hooks:
+      - id: ruff   # Linting
+
+  - repo: https://github.com/psf/black
+    rev: stable
+    hooks:
+      - id: black  # formatting
diff --git a/src/__init__.py b/src/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/codewars/counting_duplicates.py b/src/codewars/counting_duplicates.py
new file mode 100644
index 0000000..d44ffca
--- /dev/null
+++ b/src/codewars/counting_duplicates.py
@@ -0,0 +1,14 @@
+# Abgabe - Counting Duplicates Aufgabe von Codewars
+# Link dazu: https://www.codewars.com/kata/54bf1c2cd5b56cc47f0007a1
+# Leart Ramushi
+
+
+def duplicate_count(text):
+    lower_text = text.lower()
+    letter_set = set()
+
+    for i in range(len(lower_text)):
+        if lower_text.count(lower_text[i]) > 1:
+            letter_set.add(lower_text[i])
+
+    return len(letter_set)
diff --git a/src/moduleA.py b/src/moduleA.py
new file mode 100644
index 0000000..b7f0906
--- /dev/null
+++ b/src/moduleA.py
@@ -0,0 +1,10 @@
+def addition(a=1, b=2):
+    return a + b
+
+
+def f(x: int, y: int) -> int:
+    return x + y
+
+
+if __name__ == "__main__":
+    print(addition(5, 5))
diff --git a/tests/test_moduleA.py b/tests/test_moduleA.py
new file mode 100644
index 0000000..42fe6cc
--- /dev/null
+++ b/tests/test_moduleA.py
@@ -0,0 +1,6 @@
+from src.moduleA import addition
+
+
+def test_a():
+    assert addition() == 3
+    assert addition(5, 5) == 10