Restore complete file with correct doctest value and error handling

Author: Tejasrahane

maths/arc_length.py

@@ -1,17 +1,20 @@
 from math import pi
 
-
 def arc_length(angle: float, radius: float) -> float:
     """
     Calculate the arc length of a circle.
+
     The arc length is the distance along the curved line making up the arc.
     Formula: arc_length = 2 * pi * radius * (angle / 360)
     Wikipedia: https://en.wikipedia.org/wiki/Arc_length
+
     Args:
         angle: The angle in degrees
         radius: The radius of the circle
+
     Returns:
         The arc length as a float
+
     >>> arc_length(45, 5)
     3.9269908169872414
     >>> arc_length(120, 15)
@@ -39,8 +42,6 @@ def arc_length(angle: float, radius: float) -> float:
         raise ValueError("angle and radius must be positive")
     return 2 * pi * radius * (angle / 360)
 
-
 if __name__ == "__main__":
     import doctest
-
     doctest.testmod()