check if the word in the string is in the list of the special words to count, if so, add to dictionary along with the number of times it occurred in the string

def word_count(special_words, string):
  words = string.split()
  special_word_counts = dict()
  for word in words:
    if word in special_words:
      if word in special_word_counts:
        special_word_counts[word] = special_word_counts[word] + 1
      else:
        special_word_counts[word] = 1
  return special_word_counts

word_count(['apple', 'banana', 'grape'], "one fish two fish apple grape grape banana fish")