/**

@struct vrna_fc_s
@scripting
@parblock

This data structure is wrapped as class @p fold_compound with several related functions attached as methods.

A new @p fold_compound can be obtained by calling one of its constructors:<br>
- @p fold_compound(seq) - Initialize with a single sequence, or two concatenated sequences
  separated by an ampersand character `&` (for cofolding)
- @p fold_compound(aln) - Initialize with a sequence alignment @em aln stored as a list
  of sequences (with gap characters).

The resulting object has a list of attached methods which in most cases directly correspond to
functions that mainly operate on the corresponding @p C data structure:<br>
- @p type() - Get the type of the @em fold_compound (See #vrna_fc_type_e)
- @p length() - Get the length of the sequence(s) or alignment stored within the @p fold_compound.

See, e.g.
@rstinline:py:class:`RNA.fold_compound` in the :doc:`/api_python`@endrst.
@endparblock
*/
