code: private String getMismatchedPartitioner(Class<? extends IPartitioner> expectedPartitioner) {
          String partitioner = null;
          try {
              partitioner = _astyanaxKeyspace.describePartitioner();
              boolean matches = CassandraPartitioner.fromClass(partitioner).matches(expectedPartitioner.getName());
              if (matches) {
                  return null;
              } else {
                  return partitioner;
              }
          } catch (ConnectionException e) {
              throw Throwables.propagate(e);
          } catch (IllegalArgumentException e) {
              // Only thrown if the partitioner doesn't match any compatible partitioner, so by definition it is mismatched.
              return partitioner;
          }
  
      }
docs: Returns the actual partitioner in use by Cassandra if it does not match the expected partitioner, null if it matches.