code: def get(self, server):
          
          if not isinstance(server, six.binary_type):
              server = server.encode('utf-8')
          data = self._execute('get', server)
          result = json.loads(data.decode('utf-8'))
  
          # docker-credential-pass will return an object for inexistent servers
          # whereas other helpers will exit with returncode != 0. For
          # consistency, if no significant data is returned,
          # raise CredentialsNotFound
          if result['Username'] == '' and result['Secret'] == '':
              raise errors.CredentialsNotFound(
                  'No matching credentials in {}'.format(self.program)
              )
  
          return result
docs: Retrieve credentials for `server`. If no credentials are found,
              a `StoreError` will be raised.