input: Write a function to compute the area of a circle given its radius. Return the area rounded to two decimal places. If the radius is negative or zero, return 'Invalid radius'.
  def area_circle(radius):
      if radius <= 0:
          return 'Invalid radius'
      return round(math.pi * (radius ** 2), 2)
  assert area_circle(5) == 78.54
  assert area_circle(0) == 'Invalid radius'
  assert area_circle(-3) == 'Invalid radius'
  assert area_circle(10) == 314.16
output: def area_circle(radius):
      if radius <= 0:
          return 'Invalid radius'
      return round(math.pi * (radius ** 2), 2)