code: def _GetAccountsData(self, metadata_dict):
      
      instance_data, project_data = self._GetInstanceAndProjectAttributes(
          metadata_dict)
      valid_keys = [instance_data.get('sshKeys'), instance_data.get('ssh-keys')]
      block_project = instance_data.get('block-project-ssh-keys', '').lower()
      if block_project != 'true' and not instance_data.get('sshKeys'):
        valid_keys.append(project_data.get('ssh-keys'))
        valid_keys.append(project_data.get('sshKeys'))
      accounts_data = '\n'.join([key for key in valid_keys if key])
      return self._ParseAccountsData(accounts_data)
docs: Get the user accounts specified in metadata server contents.
  
      Args:
        metadata_dict: json, the deserialized contents of the metadata server.
  
      Returns:
        dict, a mapping of the form: {'username': ['sshkey1, 'sshkey2', ...]}.