
[;1m  constant_function(Set, AnySet)[0m

  Creates the function that maps each element of set [;;4mSet[0m onto [;;4m[0m
  [;;4mAnySet[0m.

    1> S = sofs:set([a,b]),
    E = sofs:from_term(1),
    R = sofs:constant_function(S, E),
    sofs:to_external(R).
    [{a,1},{b,1}]
