
  [;1m-spec from_term(Term) -> AnySet when AnySet :: anyset(), Term :: term().[0m

  Creates an element of Sets by traversing term [;;4mTerm[0m, sorting
  lists, removing duplicates, and deriving or verifying a valid
  type for the so obtained external set. An explicitly specified 
  type [;;4mType[0m can be used to limit the depth of the traversal; an
  atomic type stops the traversal, as shown by the following example
  where [;;4m"foo"[0m and [;;4m{"foo"}[0m are left unmodified:

    1> S = sofs:from_term([{{"foo"},[1,1]},{"foo",[2,2]}],
    [{atom,[atom]}]),
    sofs:to_external(S).
    [{{"foo"},[1]},{"foo",[2]}]

  [;;4mfrom_term[0m can be used for creating atomic or ordered sets. The
  only purpose of such a set is that of later building unordered
  sets, as all functions in this module that do anything operate
  on unordered sets. Creating unordered sets from a collection of
  ordered sets can be the way to go if the ordered sets are big and
  one does not want to waste heap by rebuilding the elements of the
  unordered set. The following example shows that a set can be built
  "layer by layer":

    1> A = sofs:from_term(a),
    S = sofs:set([1,2,3]),
    P1 = sofs:from_sets({A,S}),
    P2 = sofs:from_term({b,[6,5,4]}),
    Ss = sofs:from_sets([P1,P2]),
    sofs:to_external(Ss).
    [{a,[1,2,3]},{b,[4,5,6]}]

  Other functions that create sets are [;;4mfrom_external/2[0m and [;;4m[0m
  [;;4mfrom_sets/1[0m. Special cases of [;;4mfrom_term/2[0m are [;;4ma_function/1,2[0m, [;;4m[0m
  [;;4mempty_set/0[0m, [;;4mfamily/1,2[0m, [;;4mrelation/1,2[0m, and [;;4mset/1,2[0m.
