input: 
  # Response:
  Write a function to calculate the square root of a user-defined positive number. The function should return the result.
  import math
  
  def calc_sqrt(n):
      return math.sqrt(n)
  
  # Test cases:
  assert calc_sqrt(100) == 10.0
  assert calc_sqrt(25) == 5.0
  assert calc_sqrt(0) == 0.0
  assert calc_sqrt(225) == 15.0
  assert calc_sqrt(16.5) == 4.06155281280883
  
output:     
      return math.sqrt(n)
  