input: Write a function to find the mode of the given set of values. The mode is the value that appears most frequently in the set. If there are multiple modes, return the first one encountered. If the given set is empty, return None.
  def find_mode(list):
      if not list:
          return None
      max_count = 0
      mode = list[0]
      count = {}
      for item in list:
          if item in count:
              count[item] += 1
          else:
              count[item] = 1
          if count[item] > max_count:
              max_count = count[item]
              mode = item
      return mode
  
  assert find_mode([1, 2, 3, 2, 4, 2]) == 2
  assert find_mode([1, 1, 2, 2, 3]) == 1  # or 2 since both appear twice
  assert find_mode([1, 2, 3, 4, 5]) == 1  # All elements appear once, return the first
  assert find_mode([]) == None
  assert find_mode([1, 1, 1, 2, 2]) == 1
output: def find_mode(list):
      if not list:
          return None
      max_count = 0
      mode = list[0]
      count = {}
      for item in list:
          if item in count:
              count[item] += 1
          else:
              count[item] = 1
          if count[item] > max_count:
              max_count = count[item]
              mode = item
      return mode