input: Write a function to tokenize a given text using the NLTK library. Return the list of tokens.
  assert tokenize_text('Python is an interpreted, high-level, general-purpose programming language.')==['Python', 'is', 'an', 'interpreted', ',', 'high-level', ',', 'general-purpose', 'programming', 'language', '.']
  assert tokenize_text('')==[]
  assert tokenize_text('Hello World!')==['Hello', 'World', '!']
  assert tokenize_text('This is a test.')==['This', 'is', 'a', 'test', '.']
  assert tokenize_text('Tokenize this text.')==['Tokenize', 'this', 'text', '.']
output: def tokenize_text(text):
      from nltk.tokenize import word_tokenize
      return word_tokenize(text)