input: Write a function to calculate the area of a circle given its radius. If the radius is negative then raise an error as the radius cannot be negative. Use the formula: area = π * (radius ** 2).
  assert area_circle(5) == 78.54
  assert area_circle(0) == 0.0
  assert area_circle(7) == 153.94
  assert area_circle(-3) raises an error
  assert area_circle(10) == 314.16
output: def area_circle(radius):
      if radius < 0:
          raise ValueError("Radius cannot be negative")
      return 3.1416 * (radius ** 2)