input: Write a function to count the occurrence of each character in a given input string. Return a dictionary where the keys are the characters and the values are the counts of those characters.
  
  def char_occurrences(a_string):
   char_count = {}
   for char in a_string:
       if char in char_count:
           char_count[char] += 1
       else:
           char_count[char] = 1
   return char_count
  
  input_string = "Hello, World!"
  print(char_occurrences(input_string))
  
  # Output
  # {'H': 1, 'e': 1, 'l': 3, 'o': 2, ',': 1, ' ': 1, 'W': 1, 'r': 1, 'd': 1, '!': 1}
output: def char_occurrences(a_string):
      char_count = {}
      for char in a_string:
          if char in char_count:
              char_count[char] += 1
          else:
              char_count[char] = 1
      return char_count