def add_tags(ResourceId=None, TagsList=None):
    """
    Adds one or more tags to a trail, up to a limit of 50. Tags must be unique per trail. Overwrites an existing tag's value when a new value is specified for an existing tag key. If you specify a key without a value, the tag will be created with the specified key and a value of null. You can tag a trail that applies to all regions only from the region in which the trail was created (that is, from its home region).
    See also: AWS API Documentation
    
    
    :example: response = client.add_tags(
        ResourceId='string',
        TagsList=[
            {
                'Key': 'string',
                'Value': 'string'
            },
        ]
    )
    
    
    :type ResourceId: string
    :param ResourceId: [REQUIRED]
            Specifies the ARN of the trail to which one or more tags will be added. The format of a trail ARN is:
            arn:aws:cloudtrail:us-east-1:123456789012:trail/MyTrail
            

    :type TagsList: list
    :param TagsList: Contains a list of CloudTrail tags, up to a limit of 50
            (dict) --A custom key-value pair associated with a resource such as a CloudTrail trail.
            Key (string) -- [REQUIRED]The key in a key-value pair. The key must be must be no longer than 128 Unicode characters. The key must be unique for the resource to which it applies.
            Value (string) --The value in a key-value pair of a tag. The value must be no longer than 256 Unicode characters.
            
            

    :rtype: dict
    :return: {}
    
    
    """
    pass
