input: Write a function to calculate the square root of a given positive number using the `math.sqrt` function. If the input number is negative, raise a ValueError.
  assert calculate_square_root(100) == 10.0
  assert calculate_square_root(16) == 4.0
  assert calculate_square_root(25) == 5.0
  assert calculate_square_root(0) == 0.0
  try:
      calculate_square_root(-4)
  except ValueError as e:
      assert str(e) == 'Input number must be positive'
output: import math
  
  def calculate_square_root(number):
      if number < 0:
          raise ValueError('Input number must be positive')
      return math.sqrt(number)