Generate a new %Bio.Sequence.DnaDoubleStrand{} struct.

Options

label - This is a label applied to the top and bottom. alphabet - This is the alphabet to use for the top and bottom strands, defaults to the Bio.Sequence.Alphabets.Dna.iupac/0. This allows the most general use of the new function in unknown scenarios. complement_offset - Offset for the strands. Positive values are considered offset to top, negative as offset to bottom. E.g. 5 would give 5 nt offset on top, leading to a bottom strand overhand on the 5' side and a top strand overhang on the 3' side.