code: def import_vmesh(file):
      
      imported_elements = []
      if os.path.isfile(file):
          imported_elements.append(exch.import_vol_mesh(file))
      elif os.path.isdir(file):
          files = sorted([os.path.join(file, f) for f in os.listdir(file)])
          for f in files:
              imported_elements.append(exch.import_vol_mesh(f))
      else:
          raise exch.GeomdlException("Input is not a file or a directory")
      return imported_elements
docs: Imports NURBS volume(s) from volume mesh (vmesh) file(s).
  
      :param file: path to a directory containing mesh files or a single mesh file
      :type file: str
      :return: list of NURBS volumes
      :rtype: list
      :raises GeomdlException: an error occurred reading the file