input: Write a python function to calculate the square root of a number using the Babylonian method.
  assert abs(sqrt(4) - 2) < 0.0001
  assert abs(sqrt(16) - 4) < 0.0001
  assert abs(sqrt(25) - 5) < 0.0001
output: def sqrt(n):
      if n < 0:
          raise ValueError("Cannot compute the square root of a negative number")
      guess = n / 2.0
      tolerance = 0.0001
      while True:
          new_guess = (guess + n / guess) / 2.0
          if abs(new_guess - guess) < tolerance:
              return new_guess
          guess = new_guess