replace (default): This is the normal behavior. Existing content is 

replaced completely by the imported content, i.e. is overridden or 

deleted accordingly.

​

merge (deprecated): Existing content is not modified, i.e. only new 

content is added and none is deleted or modified. Deprecated, as not 

handled consistently, use merge_properties instead.

​

merge_properties (recommended): Existing content is not modified, i.e. 

only new content is added and none is deleted or modified.

​

update (deprecated): Existing content is updated, new content is added 

and none is deleted. Deprecated, as not handled consistently, use 

update_properties instead.

​

update_properties (recommended): Existing content is updated, new 

content is added and none is deleted.