Deletes a list of flow requests from the database.

def DeleteFlowRequests(self, requests, cursor=None):
    """Deletes a list of flow requests from the database."""
    if not requests:
      return

    conditions = []
    args = []
    for r in requests:
      conditions.append("(client_id=%s AND flow_id=%s AND request_id=%s)")
      args.append(db_utils.ClientIDToInt(r.client_id))
      args.append(db_utils.FlowIDToInt(r.flow_id))
      args.append(r.request_id)

    req_query = "DELETE FROM flow_requests WHERE " + " OR ".join(conditions)
    res_query = "DELETE FROM flow_responses WHERE " + " OR ".join(conditions)

    cursor.execute(res_query, args)
    cursor.execute(req_query, args)