Deletes a list of flow processing requests from the database.

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

    query = "DELETE FROM flow_processing_requests WHERE "

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

    query += " OR ".join(conditions)
    cursor.execute(query, args)