=> operator for named parameters in open cursor

Since Postgres 9.5 it is possible to use the => operators for filling in 
named parameters in a function call, like perform my_func(named_param => 
'some value'). The old form, with the := operator is still allowed for 
backward reference.

But with open cursor, still only the old := operator is allowed. 
Wouldn't it be more appropriate to at least allow the => operator there 
as well, like open my_cursor(named_param => 'some value')?