code: def get_column(self, key):
          
          if isinstance(key, int):
              index = key
          elif isinstance(key, basestring):
              index = self.get_column_index(key)
          else:
              raise TypeError(("key must be an int or str, "
                               "not {}").format(type(key).__name__))
          return iter(map(operator.itemgetter(index), self._table))
docs: Return an iterator to a column.
  
          Parameters
          ----------
          key : int, str
              index of the column, or the header of the column.
              If index is specified, then normal list rules apply.
  
          Raises
          ------
          TypeError:
              If key is not of type `int`, or `str`.
  
          Returns
          -------
          iter:
              Iterator to the specified column.