def extend(self, iterable):
        """ Concatenate two lists by adding a list of extra items to the end
        of this list. Each item added must be capable of being unpacked into a
        key-value pair.

        >>> kvl = KeyValueList([('one', 'eins'), ('two', 'zwei')])
        >>> kvl.extend([('three', 'drei'), ('four', 'vier')])
        >>> for item in kvl:
        ...     print(item)
        ('one', 'eins')
        ('two', 'zwei')
        ('three', 'drei')
        ('four', 'vier')
        >>> kvl.extend(['five', 'six'])
        Traceback (most recent call last):
          File "<stdin>", line 1, in ?
        ValueError: KeyValueList items must be pairs

        """
        if isinstance(iterable, Mapping):
            list.extend(self, iterable.items())
        else:
            try:
                list.extend(self, ((k, v) for k, v in iterable))
            except __HOLE__:
                raise ValueError("KeyValueList items must be pairs")
dataset/ETHPy150Open nigelsmall/httpstream/httpstream/kvlist.py/KeyValueList.extend