diff --git a/maths/volume_of_cylinder.py b/maths/volume_of_cylinder.py
new file mode 100644
index 000000000000..499c0c9ebe69
--- /dev/null
+++ b/maths/volume_of_cylinder.py
@@ -0,0 +1,25 @@
+import math
+
+
+def volume_of_cylinder(radius: float, height: float) -> float:
+    """
+    Calculate the volume of a cylinder.
+    Formula: pi * radius^2 * height
+    Examples:
+    >>> volume_of_cylinder(3.0, 5.0)
+    141.37
+    >>> volume_of_cylinder(2.5, 4.0)
+    78.54
+    >>> volume_of_cylinder(0.0, 5.0)
+    0.0
+    """
+    if radius < 0 or height < 0:
+        raise ValueError("Radius and height cannot be negative")
+    volume = math.pi * (radius**2) * height
+    return round(volume, 2)
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
diff --git a/maths/zellers_congruence.py b/maths/zellers_congruence.py
index b958ed3b8659..12ebe6c57f01 100644
--- a/maths/zellers_congruence.py
+++ b/maths/zellers_congruence.py
@@ -1,5 +1,5 @@
 import argparse
-import datetime
+import datetime as dt
 
 
 def zeller(date_input: str) -> str:
@@ -120,7 +120,7 @@ def zeller(date_input: str) -> str:
         )
 
     # Get datetime obj for validation
-    dt_ck = datetime.date(int(y), int(m), int(d))
+    dt_ck = dt.date(int(y), int(m), int(d))
 
     # Start math
     if m <= 2: