diff --git a/README.md b/README.md
index a258773..4e59365 100644
--- a/README.md
+++ b/README.md
@@ -20,5 +20,5 @@ autopep8 --in-place code/myfile.py
 
 
  mypy .                                                                                                                                                                                                                            
-  pylint $(git ls-files '*.py') --fail-under=8.0                                                                                                                                                                                    
-  pytest --cov=. --cov-fail-under=80          
\ No newline at end of file
+ pylint $(git ls-files '*.py') --fail-under=8.0                                                                                                                                                                                    
+ pytest --cov=. --cov-fail-under=80          
\ No newline at end of file
diff --git a/code/calculator.py b/code/calculator.py
deleted file mode 100644
index 0fa0a54..0000000
--- a/code/calculator.py
+++ /dev/null
@@ -1,4 +0,0 @@
-"""A simple calculator module that provides basic arithmetic operations."""
-def add(a: float, b: float) -> int:
-    """Add two numbers and return the result."""
-    return a + b
diff --git a/code/__init__.py b/src/__init__.py
similarity index 100%
rename from code/__init__.py
rename to src/__init__.py
diff --git a/src/calculator.py b/src/calculator.py
new file mode 100644
index 0000000..77e1607
--- /dev/null
+++ b/src/calculator.py
@@ -0,0 +1,4 @@
+"""A simple calculator module that provides basic operations."""
+def add(a: float, b: float) -> float:
+    """Add two numbers and return the result."""
+    return a + b
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_calculator.py b/tests/test_calculator.py
index 81f80c7..dabf164 100644
--- a/tests/test_calculator.py
+++ b/tests/test_calculator.py
@@ -1,19 +1,23 @@
-import pytest
+"""Unit tests for the calculator module."""
 
-from code.calculator import add
+from src.calculator import add
 
 
 def test_add_positive_numbers() -> None:
+    """Test adding two positive numbers."""
     assert add(2, 3) == 5
 
 
 def test_add_negative_numbers() -> None:
+    """Test adding two negative numbers."""
     assert add(-2, -3) == -5
 
 
 def test_add_mixed_numbers() -> None:
+    """Test adding a positive and a negative number."""
     assert add(-2, 5) == 3
 
 
 def test_add_floats() -> None:
+    """Test adding two floating-point numbers."""
     assert add(2.5, 3.5) == 6.0