code: def iterate_ngrams(text, n):
      
      if n <= 0:
          raise ValueError("n must be a positive integer")
  
      return [text[i: i + n] for i in range(len(text) - n + 1)]
docs: Generator to yield ngrams in ``text``.
  
      Example:
          >>> for ngram in iterate_ngrams("example", 4):
          ...     print(ngram)
          exam
          xamp
          ampl
          mple
  
      Args:
          text (str): text to iterate over
          n (int): size of window for iteration
  
      Returns:
          Generator expression to yield the next ngram in the text
  
      Raises:
          ValueError: If n is non positive