code: def _get_abs_filepath(self, ifile):
          
          assert ifile is not None
          ifile = ifile[7:] if ifile.startswith('file://') else ifile
          if ifile[0] != '/':
              basedir = os.path.abspath(os.path.dirname(self.config_file))
              ifile = os.path.join(basedir, ifile)
          return 'file://' + ifile
docs: validate src or dst file path with self.config_file