input: Write a python function to generate and display a word cloud from a given text using WordCloud and matplotlib.
  assert generate_wordcloud('The quick brown fox jumps over the lazy dog.') is None
  assert generate_wordcloud('Hello world, hello universe') is None
  assert generate_wordcloud('Python is amazing. Python is versatile.') is None
output: def generate_wordcloud(text):
      from wordcloud import WordCloud
      import matplotlib.pyplot as plt
      
      wordcloud = WordCloud(width=800, height=400, background_color='white').generate(text)
      
      plt.figure(figsize=(10, 5))
      plt.imshow(wordcloud, interpolation='bilinear')
      plt.axis('off')
      plt.show()