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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_all_events(self, source_identifier=None, source_type=None, start_time=None, end_time=None, max_records=None, marker=None):
 """ 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` """

        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)])