def timesteps(self):
        """
        Time-step at which this intervention occurs, starting from 0, the first intervention-period time-step.
        https://github.com/SwissTPH/openmalaria/wiki/GeneratedSchema32Doc#-deploy-1
        rtype: list
        """
        timesteps = []
        timed = self.et.find("timed")

        if timed is not None:
            for deploy in timed.findall("deploy"):
                timesteps.append(deploy.attrib["time"])

        return timesteps