input: Write a function to tokenize a given text using the NLTK library. The function should return a list of tokens. If the input text is empty, the function should return an empty list.
  import nltk 
  from nltk.tokenize import word_tokenize 
    
  def tokenize_text(text):
      if not text:
          return []
      return word_tokenize(text)
  
  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('')==[]
output: def tokenize_text(text):
      if not text:
          return []
      return word_tokenize(text)