def METHOD_NAME(self, direction):
    """
    Internal method for determining left or right client.
    Negative direction is to left
    """
    column, row = self.column, self.row
    column = (column + direction) % len(self.get_row(row))
    self.clients.current_index = row * self.columns + column
    self.group.focus(self.clients.current_client)