input: Write a python function to count the occurrence of each character in a string.
  assert char_count("Programming") == {'P': 1, 'r': 2, 'o': 1, 'g': 2, 'a': 1, 'm': 2, 'i': 1, 'n': 1}
  assert char_count("hello") == {'h': 1, 'e': 1, 'l': 2, 'o': 1}
  assert char_count("aabbcc") == {'a': 2, 'b': 2, 'c': 2}
output: def char_count(s):
      result = {}
      for char in s:
          if char in result:
              result[char] += 1
          else:
              result[char] = 1
      return result