code: def get_all_events(self, source_identifier=None, source_type=None,
                         start_time=None, end_time=None,
                         max_records=None, marker=None):
          
          params = {}
          if source_identifier and source_type:
              params['SourceIdentifier'] = source_identifier
              params['SourceType'] = source_type
          if start_time:
              params['StartTime'] = start_time.isoformat()
          if end_time:
              params['EndTime'] = end_time.isoformat()
          if max_records:
              params['MaxRecords'] = max_records
          if marker:
              params['Marker'] = marker
          return self.get_list('DescribeEvents', params, [('Event', Event)])
docs: Get information about events related to your DBInstances,
          DBSecurityGroups and DBParameterGroups.
  
          :type source_identifier: str
          :param source_identifier: If supplied, the events returned will be
                                    limited to those that apply to the identified
                                    source.  The value of this parameter depends
                                    on the value of source_type.  If neither
                                    parameter is specified, all events in the time
                                    span will be returned.
  
          :type source_type: str
          :param source_type: Specifies how the source_identifier should
                              be interpreted.  Valid values are:
                              b-instance | db-security-group |
                              db-parameter-group | db-snapshot
  
          :type start_time: datetime
          :param start_time: The beginning of the time interval for events.
                             If not supplied, all available events will
                             be returned.
  
          :type end_time: datetime
          :param end_time: The ending of the time interval for events.
                           If not supplied, all available events will
                           be returned.
  
          :type max_records: int
          :param max_records: The maximum number of records to be returned.
                              If more results are available, a MoreToken will
                              be returned in the response that can be used to
                              retrieve additional records.  Default is 100.
  
          :type marker: str
          :param marker: The marker provided by a previous request.
  
          :rtype: list
          :return: A list of class:`boto.rds.event.Event`