The "parameter" function will assume the first argument is always the parameter name, whilst
the value of the returned map will be:
- its context (the feature collection or the coverage)
if the argument is just one (which is assumed to be the process parameter name)
- the second argument if there are only two
- a List collecting all of the arguments besides the first if there are more than two
This takes care of all the normal needs, that is, passing the source dataset to the process,
passing a given single valued argument, or passing down a multivalued argument.