input: Write a function that takes a list containing fruit names and returns the most common fruit name. If there are multiple fruits with the same highest frequency, return any one of them. If the list is empty, return None.
  def most_common_fruit(fruit_list):
      if not fruit_list:
          return None
      
      freq_dict = {}
      for fruit in fruit_list:
          if fruit in freq_dict:
              freq_dict[fruit] += 1
          else:
              freq_dict[fruit] = 1
      
      max_freq = max(freq_dict.values())
      for fruit, freq in freq_dict.items():
          if freq == max_freq:
              return fruit
  
  assert most_common_fruit(['Apple', 'Orange', 'Apple', 'Pineapple', 'Grape', 'Apple']) == 'Apple'
  assert most_common_fruit(['Orange', 'Apple', 'Pineapple', 'Grape', 'Orange', 'Apple']) == 'Apple' or assert most_common_fruit(['Orange', 'Apple', 'Pineapple', 'Grape', 'Orange', 'Apple']) == 'Orange'
  assert most_common_fruit([]) == None
output: def most_common_fruit(fruit_list):
      if not fruit_list:
          return None
      
      freq_dict = {}
      for fruit in fruit_list:
          if fruit in freq_dict:
              freq_dict[fruit] += 1
          else:
              freq_dict[fruit] = 1
      
      max_freq = max(freq_dict.values())
      for fruit, freq in freq_dict.items():
          if freq == max_freq:
              return fruit