anyelement -> anyrange

Any reason why we can create a function that accepts anyelement and 
returns anyarray, but can't do the same with anyrange? Could we attempt 
to match each range subtype looking for a match?

create function range__create(anyelement,anyelement,text = '[]') RETURNS 
anyrange LANGUAGE plpgsql AS $body$
BEGIN
RETURN int4range($1,$2,$3)
END$body$;
ERROR:  42P13: cannot determine result data type
DETAIL:  A function returning "anyrange" must have at least one 
"anyrange" argument.

create function array__create(anyelement,anyelement) RETURNS anyarray 
LANGUAGE plpgsql AS $body$
BEGIN
RETURN array[$1,$2];
END$body$;
CREATE FUNCTION
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Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
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