code: def serialize_operator_not_equal(self, op):
          
          elem = etree.Element('not-equals')
          return self.serialize_value_list(elem, op.args)
docs: Serializer for :meth:`SpiffWorkflow.operators.NotEqual`.
  
          Example::
  
              <not-equals>
                  <value>text</value>
                  <value><attribute>foobar</attribute></value>
                  <value><path>foobar</path></value>
              </not-equals>