docs: def _load_files(self):
          """Load other files"""
  
          def copy_dir(path):
              for (dr, _, files) in walk(path):
                  for fn in files:
  
                      if '__pycache__' in fn:
                          continue
  
                      relpath = dr.replace(self.source_dir, '').strip('/')
                      src = parse_app_url(join(dr, fn))
                      dest = join(relpath, fn)
  
                      resource = src.get_resource()
  
                      self._load_file( dest, resource.read())
  
          for term in self.resources(term = 'Root.Pythonlib'):
  
              uv = parse_app_url(term.value)
              ur = parse_app_url(self.source_dir)
  
              # In the case that the input doc is a file, and the ref is to a file,
              # try interpreting the file as relative.
              if ur.proto == 'file' and uv.proto == 'file':
  
                  # Either a file or a directory
                  path = join(self.source_dir, uv.path)
                  if isdir(path):
                      copy_dir(path)
  
              else:
                  # Load it as a URL
                  f = self._get_ref_contents(term)
                  try:
                      self._load_file(term.value,f.read() )
                  except Exception as e:
                      raise PackageError("Failed to load file for '{}': {} ".format(term.value, e))
  
          nb_dir = join(self.source_dir, 'notebooks')
  
          if exists(nb_dir) and isdir(nb_dir):
              copy_dir(nb_dir)