code: def from_sequence(cls, sequence, phos_3_prime=False):
          
          strand1 = NucleicAcidStrand(sequence, phos_3_prime=phos_3_prime)
          duplex = cls(strand1)
          return duplex
docs: Creates a DNA duplex from a nucleotide sequence.
  
          Parameters
          ----------
          sequence: str
              Nucleotide sequence.
          phos_3_prime: bool, optional
              If false the 5' and the 3' phosphor will be omitted.