input: 
  class MedianFinder:
      """A class to find the median of an unsorted list of numbers.
  
      This class provides methods to add numbers to the list and to find the median 
      of the numbers currently in the list.
  
      Example:
      >>> median_finder = MedianFinder()
      >>> median_finder.add(1)
      >>> median_finder.add(3)
      >>> median_finder.add(2)
      >>> median_finder.find_median()
      2.0
      """
      def __init__(self):
          self._data = []
  
      def add(self, num):
          self._data.append(num)
  
      def find_median(self):
          data = sorted(self._data)
          n = len(data)
          return (data[(n-1)//2] + data[n//2])/2
  
output:     
      def __init__(self):
          self._data = []
  
      def add(self, num):
          self._data.append(num)
  
      def find_median(self):
          data = sorted(self._data)
          n = len(data)
          return (data[(n-1)//2] + data[n//2])/2
  