def METHOD_NAME(
    self,
    function: Callable[
        [_FirstType],
        Kind2['Pair', _NewFirstType, _SecondType],
    ],
) -> 'Pair[_NewFirstType, _SecondType]':
    """
    Changes the first type with a function returning another ``Pair``.
    >>> def bindable(first: int) -> Pair[str, str]:
    ...     return Pair((str(first), ''))
    >>> assert Pair((1, 'b')).bind(bindable) == Pair(('1', ''))
    """
    return dekind(function(self._inner_value[0]))