code: def get(self, ii, default=None, msg_if_none=None):
          
          try:
              out = self[ii]
  
          except (IndexError, ValueError):
              if default is not None:
                  out = default
  
              else:
                  if msg_if_none is not None:
                      raise ValueError(msg_if_none)
  
                  else:
                      raise
  
          return out
docs: Get an item from Container - a wrapper around
          Container.__getitem__() with defaults and custom error message.
  
          Parameters
          ----------
          ii : int or str
              The index or name of the item.
          default : any, optional
              The default value returned in case the item `ii` does not exist.
          msg_if_none : str, optional
              If not None, and if `default` is None and the item `ii` does
              not exist, raise ValueError with this message.