Takes a SingleStrandHelix and creates the antisense strand.

def generate_complementary_strand(strand1):
        """Takes a SingleStrandHelix and creates the antisense strand."""
        rise_adjust = (
            strand1.rise_per_nucleotide * strand1.axis.unit_tangent) * 2
        strand2 = NucleicAcidStrand.from_start_and_end(
            strand1.helix_end - rise_adjust, strand1.helix_start - rise_adjust,
            generate_antisense_sequence(strand1.base_sequence),
            phos_3_prime=strand1.phos_3_prime)
        ad_ang = dihedral(strand1[0]["C1'"]._vector, strand1.axis.start,
                          strand2.axis.start + rise_adjust,
                          strand2[-1]["C1'"]._vector)
        strand2.rotate(
            225.0 + ad_ang, strand2.axis.unit_tangent,
            point=strand2.helix_start)  # 225 is the base adjust
        return strand2