<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_rdataset(self, rdclass, rdtype, covers=dns.rdatatype.NONE, create=False):
 """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 """


        try:
            rds = self.find_rdataset(rdclass, rdtype, covers, create)
        except KeyError:
            rds = None
        return rds