input: def calculate_gini_coefficient(dataset: List[float]) -> float:
      """
      Calculate the Gini coefficient of a given dataset.
  
      Example:
      >>> calculate_gini_coefficient([2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,21])
      0.605
      """
output:     n = len(dataset)
      if n == 0:
          return 0.0
      dataset.sort()
      total_sum = sum(dataset)
      gini_sum = 0.0
      for i in range(n):
          gini_sum += (2 * (i + 1) - n - 1) * dataset[i]
      return gini_sum / (n * total_sum)