This returns a list of all deletions (i.e., residue ranges in which gaps in the model sequence, which must be the last in the alignment aln, are aligned to residues in the other sequences). Each residue range is extended by extension residues either side of the deletion.
If include_termini is False, any residue range that includes a chain terminus is excluded from the output.
See also Model.get_insertions(), Model.loops().Example: See Selection() command.