Returns True if there's a currently running iteration of this job.

def IsRunning(self):
    """Returns True if there's a currently running iteration of this job."""
    current_urn = self.Get(self.Schema.CURRENT_FLOW_URN)
    if not current_urn:
      return False

    try:
      current_flow = aff4.FACTORY.Open(
          urn=current_urn, aff4_type=flow.GRRFlow, token=self.token, mode="r")
    except aff4.InstantiationError:
      # This isn't a flow, something went really wrong, clear it out.
      logging.error("Unable to open cron job run: %s", current_urn)
      self.DeleteAttribute(self.Schema.CURRENT_FLOW_URN)
      self.Flush()
      return False

    return current_flow.GetRunner().IsRunning()