code: public <T> Result<T> query(final Class<T> entityClass, final Statement statement) {
      Mapper<T> mapper = mapper(entityClass);
      Session session = mapper.getManager().getSession();
      ResultSet rs = session.execute(statement);
      return mapper.map(rs);
    }
docs: Execute a query and map result to entityClass.
  
  @param entityClass Entity class.
  @param statement Statement to execute.
  @return A query result.