input: def char_occurrences(a_string: str) -> dict:
      """ Given an input string, count the occurrence of each character in the string.
      >>> char_occurrences("Hello, World!")
      {'H': 1, 'e': 1, 'l': 3, 'o': 2, ',': 1, ' ': 1, 'W': 1, 'r': 1, 'd': 1, '!': 1}
      """
      char_count = {}
      for char in a_string:
          if char in char_count:
              char_count[char] += 1
          else:
              char_count[char] = 1
      return char_count
output:     char_count = {}
      for char in a_string:
          if char in char_count:
              char_count[char] += 1
          else:
              char_count[char] = 1
      return char_count