input: Write a function to edit the given Python code to prompt the user to enter the value of radius to calculate the area of a circle. If the radius is not entered, the function should use a default value of 5.
  assert calculate_area_of_circle(5)==78.5
  assert calculate_area_of_circle(10)==314.0
  assert calculate_area_of_circle(2)==12.56
  assert calculate_area_of_circle()==78.5
  assert calculate_area_of_circle(3)==28.26
output: def calculate_area_of_circle(radius=None):
      if radius is None:
          radius = 5
      return 3.14 * radius * radius