title: How to raise exception for non-existent class member?
body: <p>I have a method for automatically creating Python classes that wrap database tables, with class members that have the same name as the fields in the table.  The class files look like this:</p>
  
  <pre><code>class CpsaUpldBuildChrgResultSet(Recordset):
      def __init__(self, connection):
          super().__init__(connection)
          self.DefaultTableName = 'cpsa_upld_build_chrg_result'
          self._keyFields.append('j_trans_seq')
          self._keyFields.append('j_index')
  
      @property
      def j_trans_seq(self):
          return self.GetValue('j_trans_seq')
      @j_trans_seq.setter
      def j_trans_seq(self, value):
          self.SetKeyValue('j_trans_seq', value)
  
      @property
      def j_index(self):
          return self.GetValue('j_index')
      @j_index.setter
      def j_index(self, value):
          self.SetKeyValue('j_index', value)
  </code></pre>
  
  <p>I just found that if I try to set a value for a non-existent class member, such as J_TRANS_SEQ, no exception is thrown.  Is there something I can add to this class so that an attempt to access a non-existent member would raise an exception?</p>