This returns a list of all insertions (i.e., residue ranges in which the model sequence, which must be the last in the alignment aln, is aligned only with gaps in the other sequences). Each residue range is extended by extension residues either side of the insertion, and is only returned if it is at least minlength residues long, but not longer than maxlength.
If include_termini is False, any residue range that includes a chain terminus is excluded from the output.
See also Model.get_deletions(), Model.loops().Example: See Selection() command.