Check if a reference exists

        :param branch: The branch to check if it exists
        :return: Sha of the branch if it exists, False if it does not exist, self.ProxyError if it went wrong

def get_ref(self, branch, origin=None):
        """ Check if a reference exists

        :param branch: The branch to check if it exists
        :return: Sha of the branch if it exists, False if it does not exist, self.ProxyError if it went wrong
        """
        if not origin:
            origin = self.origin
        uri = "{api}/repos/{origin}/git/refs/heads/{branch}".format(
            api=self.github_api_url,
            origin=origin,
            branch=branch
        )
        data = self.request("GET", uri)
        if data.status_code == 200:
            data = json.loads(data.content.decode("utf-8"))
            if isinstance(data, list):
                # No addresses matches, we get search results which stars with {branch}
                return False
            #  Otherwise, we get one record
            return data["object"]["sha"]
        elif data.status_code == 404:
            return False
        else:
            decoded_data = json.loads(data.content.decode("utf-8"))
            return self.ProxyError(
                data.status_code, (decoded_data, "message"),
                step="get_ref", context={
                    "uri": uri
                }
            )