diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4ea28ff
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+__pycache__/
+*.pyc
+*.pyo
+*.pyd
+.pytest_cache/
+.DS_Store
+.env
+node_modules/
+dist/
+build/
diff --git a/balancer/__pycache__/core.cpython-311.pyc b/balancer/__pycache__/core.cpython-311.pyc
deleted file mode 100644
index 87c07de..0000000
Binary files a/balancer/__pycache__/core.cpython-311.pyc and /dev/null differ
diff --git a/balancer/__pycache__/test_balancer.cpython-311-pytest-9.0.2.pyc b/balancer/__pycache__/test_balancer.cpython-311-pytest-9.0.2.pyc
deleted file mode 100644
index 6f98c7b..0000000
Binary files a/balancer/__pycache__/test_balancer.cpython-311-pytest-9.0.2.pyc and /dev/null differ
diff --git a/balancer/core.py b/balancer/core.py
index a6840c4..29373a9 100644
--- a/balancer/core.py
+++ b/balancer/core.py
@@ -6,6 +6,17 @@
 
 class InventoryItem:
     def __init__(self, sku: str, batch_id: str, current_stock: int, expiry_date: datetime.date, daily_burn_rate: float):
+        if not sku or not isinstance(sku, str):
+            raise ValueError("SKU must be a non-empty string.")
+        if not batch_id or not isinstance(batch_id, str):
+            raise ValueError("Batch ID must be a non-empty string.")
+        if not isinstance(current_stock, int) or current_stock < 0:
+            raise ValueError("Current stock must be a non-negative integer.")
+        if not isinstance(expiry_date, datetime.date):
+            raise TypeError("Expiry date must be a datetime.date object.")
+        if not isinstance(daily_burn_rate, (int, float)) or daily_burn_rate < 0:
+            raise ValueError("Daily burn rate must be a non-negative number.")
+
         self.sku = sku
         self.batch_id = batch_id
         self.current_stock = current_stock