input: Write a function to find the first non-repeating character in a given list. If there is no non-repeating character, return None. The function should check each element in the list and count its occurrences. The first element that occurs only once should be returned as the result.
  
  assert first_non_repeating_char([1, 2, 3, 4, 4, 3, 2, 1])==None
  assert first_non_repeating_char([5, 3, 4, 4, 3, 5, 2])==2
  assert first_non_repeating_char([10, 20, 30, 10, 20, 40])==30
  assert first_non_repeating_char([11, 12, 13, 14, 14, 13])==11
  assert first_non_repeating_char([7, 7, 7, 7, 7])==None
output: def first_non_repeating_char(lst):
      count = {}
      for item in lst:
          if item in count:
              count[item] += 1
          else:
              count[item] = 1
      for item in lst:
          if count[item] == 1:
              return item
      return None