code: def num_batches(n, batch_size):
      
      b = n // batch_size
      if n % batch_size > 0:
          b += 1
      return b
docs: Compute the number of mini-batches required to cover a data set of
      size `n` using batches of size `batch_size`.
  
      Parameters
      ----------
      n: int
          the number of samples in the data set
      batch_size: int
          the mini-batch size
  
      Returns
      -------
      int: the number of batches required