code: def add_reads(self, reads):
          
          if len(reads) == 0:
              return self
          new_reads = self.reads.union(reads)
          if len(new_reads) > len(self.reads):
              return VariantSequence(
                  prefix=self.prefix,
                  alt=self.alt,
                  suffix=self.suffix,
                  reads=new_reads)
          else:
              return self
docs: Create another VariantSequence with more supporting reads.