code: def ddk_filepath(self):
          
          if self.ddk_node is None: return "DDK_FILE_DOES_NOT_EXIST"
          if isinstance(self.ddk_node, FileNode): return self.ddk_node.filepath
  
          path = self.ddk_node.outdir.has_abiext("DDK")
          return path if path else "DDK_FILE_DOES_NOT_EXIST"
docs: Returns (at runtime) the absolute path of the input DKK file.