code: def index_of_coincidence(*texts):
      
      if not texts:
          raise ValueError("texts must not be empty")
  
      return statistics.mean(_calculate_index_of_coincidence(frequency_analyze(text), len(text)) for text in texts)
docs: Calculate the index of coincidence for one or more ``texts``.
      The results are averaged over multiple texts to return the delta index of coincidence.
  
      Examples:
          >>> index_of_coincidence("aabbc")
          0.2
  
          >>> index_of_coincidence("aabbc", "abbcc")
          0.2
  
      Args:
          *texts (variable length argument list): The texts to analyze
  
      Returns:
          Decimal value of the index of coincidence
  
      Raises:
          ValueError: If texts is empty
          ValueError: If any text is less that 2 character long