def describe_fleets(Names=None, NextToken=None):
    """
    If fleet names are provided, this operation describes the specified fleets; otherwise, all the fleets in the account are described.
    See also: AWS API Documentation
    
    
    :example: response = client.describe_fleets(
        Names=[
            'string',
        ],
        NextToken='string'
    )
    
    
    :type Names: list
    :param Names: The fleet names to describe. Use null to describe all the fleets for the AWS account.
            (string) --
            

    :type NextToken: string
    :param NextToken: The pagination token to use to retrieve the next page of results for this operation. If this value is null, it retrieves the first page.

    :rtype: dict
    :return: {
        'Fleets': [
            {
                'Arn': 'string',
                'Name': 'string',
                'DisplayName': 'string',
                'Description': 'string',
                'ImageName': 'string',
                'InstanceType': 'string',
                'ComputeCapacityStatus': {
                    'Desired': 123,
                    'Running': 123,
                    'InUse': 123,
                    'Available': 123
                },
                'MaxUserDurationInSeconds': 123,
                'DisconnectTimeoutInSeconds': 123,
                'State': 'STARTING'|'RUNNING'|'STOPPING'|'STOPPED',
                'VpcConfig': {
                    'SubnetIds': [
                        'string',
                    ]
                },
                'CreatedTime': datetime(2015, 1, 1),
                'FleetErrors': [
                    {
                        'ErrorCode': 'IAM_SERVICE_ROLE_MISSING_ENI_DESCRIBE_ACTION'|'IAM_SERVICE_ROLE_MISSING_ENI_CREATE_ACTION'|'IAM_SERVICE_ROLE_MISSING_ENI_DELETE_ACTION'|'NETWORK_INTERFACE_LIMIT_EXCEEDED'|'INTERNAL_SERVICE_ERROR'|'IAM_SERVICE_ROLE_IS_MISSING'|'SUBNET_HAS_INSUFFICIENT_IP_ADDRESSES'|'IAM_SERVICE_ROLE_MISSING_DESCRIBE_SUBNET_ACTION'|'SUBNET_NOT_FOUND'|'IMAGE_NOT_FOUND'|'INVALID_SUBNET_CONFIGURATION',
                        'ErrorMessage': 'string'
                    },
                ],
                'EnableDefaultInternetAccess': True|False
            },
        ],
        'NextToken': 'string'
    }
    
    
    :returns: 
    (string) --
    
    """
    pass
