code: def walk_nodes(self, node, original):
          
          try:
              # try with django-compressor<2.1
              nodelist = self.parser.get_nodelist(node, original=original)
          except TypeError:
              nodelist = self.parser.get_nodelist(node, original=original, context=None)
          for node in nodelist:
              if isinstance(node, SassSrcNode):
                  if node.is_sass:
                      yield node
              else:
                  for node in self.walk_nodes(node, original=original):
                      yield node
docs: Iterate over the nodes recursively yielding the templatetag 'sass_src'