:calls: `POST /repos/:owner/:repo/issues/:number/reactions <https://developer.github.com/v3/reactions>`_
        :param reaction_type: string
        :rtype: :class:`github.Reaction.Reaction`

def create_reaction(self, reaction_type):
        """
        :calls: `POST /repos/:owner/:repo/issues/:number/reactions <https://developer.github.com/v3/reactions>`_
        :param reaction_type: string
        :rtype: :class:`github.Reaction.Reaction`
        """
        assert isinstance(reaction_type, (str, unicode)), "reaction type should be a string"
        assert reaction_type in ["+1", "-1", "laugh", "confused", "heart", "hooray"], \
            "Invalid reaction type (https://developer.github.com/v3/reactions/#reaction-types)"

        post_parameters = {
            "content": reaction_type,
        }
        headers, data = self._requester.requestJsonAndCheck(
            "POST",
            self.url + "/reactions",
            input=post_parameters,
            headers={'Accept': Consts.mediaTypeReactionsPreview}
        )
        return github.Reaction.Reaction(self._requester, headers, data, completed=True)