def describe_entity_aggregates(eventArns=None):
    """
    Returns the number of entities that are affected by each of the specified events. If no events are specified, the counts of all affected entities are returned.
    See also: AWS API Documentation
    
    
    :example: response = client.describe_entity_aggregates(
        eventArns=[
            'string',
        ]
    )
    
    
    :type eventArns: list
    :param eventArns: A list of event ARNs (unique identifiers). For example: 'arn:aws:health:us-east-1::event/AWS_EC2_MAINTENANCE_5331', 'arn:aws:health:us-west-1::event/AWS_EBS_LOST_VOLUME_xyz'
            (string) --
            

    :rtype: dict
    :return: {
        'entityAggregates': [
            {
                'eventArn': 'string',
                'count': 123
            },
        ]
    }
    
    
    """
    pass
