code: def load(self, filename, ctx=None, allow_missing=False,
               ignore_extra=False, restore_prefix=''):
          
          if restore_prefix:
              for name in self.keys():
                  assert name.startswith(restore_prefix), \
                      "restore_prefix is '%s' but Parameters name '%s' does not start " \
                      "with '%s'"%(restore_prefix, name, restore_prefix)
          lprefix = len(restore_prefix)
          loaded = [(k[4:] if k.startswith('arg:') or k.startswith('aux:') else k, v) \
                    for k, v in ndarray.load(filename).items()]
          arg_dict = {restore_prefix+k: v for k, v in loaded}
          if not allow_missing:
              for name in self.keys():
                  assert name in arg_dict, \
                      "Parameter '%s' is missing in file '%s', which contains parameters: %s. " \
                      "Please make sure source and target networks have the same prefix."%(
                          name[lprefix:], filename, _brief_print_list(arg_dict.keys()))
          for name in arg_dict:
              if name not in self._params:
                  assert ignore_extra, \
                      "Parameter '%s' loaded from file '%s' is not present in ParameterDict, " \
                      "choices are: %s. Set ignore_extra to True to ignore. " \
                      "Please make sure source and target networks have the same prefix."%(
                          name[lprefix:], filename, _brief_print_list(self._params.keys()))
                  continue
              self[name]._load_init(arg_dict[name], ctx)
docs: Load parameters from file.
  
          Parameters
          ----------
          filename : str
              Path to parameter file.
          ctx : Context or list of Context
              Context(s) initialize loaded parameters on.
          allow_missing : bool, default False
              Whether to silently skip loading parameters not represents in the file.
          ignore_extra : bool, default False
              Whether to silently ignore parameters from the file that are not
              present in this ParameterDict.
          restore_prefix : str, default ''
              prepend prefix to names of stored parameters before loading.