code: def get_release_definition(self, project, definition_id, property_filters=None):
          
          route_values = {}
          if project is not None:
              route_values['project'] = self._serialize.url('project', project, 'str')
          if definition_id is not None:
              route_values['definitionId'] = self._serialize.url('definition_id', definition_id, 'int')
          query_parameters = {}
          if property_filters is not None:
              property_filters = ",".join(property_filters)
              query_parameters['propertyFilters'] = self._serialize.query('property_filters', property_filters, 'str')
          response = self._send(http_method='GET',
                                location_id='d8f96f24-8ea7-4cb6-baab-2df8fc515665',
                                version='5.1-preview.3',
                                route_values=route_values,
                                query_parameters=query_parameters)
          return self._deserialize('ReleaseDefinition', response)
docs: GetReleaseDefinition.
          [Preview API] Get a release definition.
          :param str project: Project ID or project name
          :param int definition_id: Id of the release definition.
          :param [str] property_filters: A comma-delimited list of extended properties to be retrieved. If set, the returned Release Definition will contain values for the specified property Ids (if they exist). If not set, properties will not be included.
          :rtype: :class:`<ReleaseDefinition> <azure.devops.v5_1.release.models.ReleaseDefinition>`