docs: def unsnip(tag=None,start=-1):
      """ This function retrieves a tagged or untagged snippet. """
      import IPython
      i = IPython.get_ipython()
      if tag in _tagged_inputs.keys():
          if len(_tagged_inputs[tag]) > 0:
              i.set_next_input(_tagged_inputs[tag][start])
      else:
          if len(_last_inputs) > 0:
              i.set_next_input(_last_inputs[start])