The relativedelta type can be applied to an existing datetime and can replace secific components of that datetime. There are two ways to build a relativedelta instance:

first, passing it two datetime classes

relativedelta(datetime1, datetime2)

second, passing it any number of the following keyword arguments

relativedelta(arg1=x, arg2=y, ...)

The order of attributtes considered when this relative data is added to a datetime is: Year Month Day Hours Minutes Seconds Microseconds