input: Write a python function to get synonyms and antonyms of a word using NLTK wordnet.
  assert get_syn_antonyms("happy") == {'synonyms': ['happy', 'felicitous'], 'antonyms': ['unhappy']}
  assert get_syn_antonyms("good") == {'synonyms': ['good', 'adept'], 'antonyms': ['bad']}
  assert get_syn_antonyms("sad") == {'synonyms': ['sad', 'unhappy'], 'antonyms': ['happy']}
output: def get_syn_antonyms(word):
      from nltk.corpus import wordnet
  
      synonyms = set()
      antonyms = set()
  
      for syn in wordnet.synsets(word):
          for lemma in syn.lemmas():
              synonyms.add(lemma.name())
              if lemma.antonyms():
                  antonyms.add(lemma.antonyms()[0].name())
  
      return {
          'synonyms': list(synonyms),
          'antonyms': list(antonyms)
  }