Tuplet number direction

[Richard Shann]

I wonder if someone could illuminate the tuplet direction property - I
wanted to put the tuplet number above rather than below and looked up:

http://lilypond.org/doc/v2.18/Documentation/internals/tupletnumber

direction (direction):

    tuplet-number::calc-direction

    If side-axis is 0 (or X), then this property determines whether the
object is placed LEFT, CENTER or RIGHT with respect to the other object.
Otherwise, it determines whether the object is placed UP, CENTER or
DOWN. Numerical values may also be used: UP=1, DOWN=-1, LEFT=-1,
RIGHT=1, CENTER=0. 

from this I tried

 \override TupletBracket #'tuplet-number::calc-direction = #UP  (WRONG)

which (having stared at LilyPond syntax over the years) looked fishy and
indeed did not work. So I resorted to stabbing in the dark:


  \override TupletBracket #'direction = #UP 

which does work. I wonder if some words of wisdom could help me and
others to go more directly to the answer in this (and other?) case(s).

Richard