input: Write a function to calculate the square root of a user-defined positive number. The function should return the square root of the number. If the number is not positive, return -1.
  assert calculate_square_root(100)==10.0
  assert calculate_square_root(25)==5.0
  assert calculate_square_root(0)==-1
  assert calculate_square_root(-10)==-1
output: def calculate_square_root(number):
      if number < 0:
          return -1
      return number ** 0.5