code: def get_rdataset(self, rdclass, rdtype, covers=dns.rdatatype.NONE,
                       create=False):
          
  
          try:
              rds = self.find_rdataset(rdclass, rdtype, covers, create)
          except KeyError:
              rds = None
          return rds
docs: Get an rdataset matching the specified properties in the
          current node.
  
          None is returned if an rdataset of the specified type and
          class does not exist and I{create} is not True.
  
          @param rdclass: The class of the rdataset
          @type rdclass: int
          @param rdtype: The type of the rdataset
          @type rdtype: int
          @param covers: The covered type.
          @type covers: int
          @param create: If True, create the rdataset if it is not found.
          @type create: bool
          @rtype: dns.rdataset.Rdataset object or None