input: Write a function to generate a string with each phrase from a given list of phrases followed by its length. If the given list is empty then return an empty string.
  
  assert generate_length_string(["A bird in the hand", "is worth two in the bush"]) == "A bird in the hand (17)is worth two in the bush (25)"
  assert generate_length_string([]) == ""
output: def generate_length_string(phrases):
      if not phrases:
          return ""
      return "".join(f"{phrase} ({len(phrase)})" for phrase in phrases)