input: Write a function to get the word with most number of occurrences in the given strings list.
  assert most_occurrences(["UTS is best for RTF", "RTF love UTS", "UTS is best"] ) == 'UTS'
  assert most_occurrences(["Its been a great year", "this year is so worse", "this year is okay"] ) == 'year'
  assert most_occurrences(["Families can be reunited", "people can be reunited", "Tasks can be achieved "] ) == 'can'
  
output: def most_occurrences(strings_list):
      word_count = {}
      for sentence in strings_list:
          words = sentence.split()
          for word in words:
              if word in word_count:
                  word_count[word] += 1
              else:
                  word_count[word] = 1
      return max(word_count, key=word_count.get)