def get_time_steps(json_file):
    """ Get time step of calculation by scenario settings.

    Parameters
    ----------
    json_file : :obj:`dict`
        Dictionary of the ``scenario_setting.json`` file

    Returns
    -------
    time_step : int
        Number of timesteps of the calculation.
    """
    end = json_file['eTraGo'].get('end_snapshot')
    start = json_file['eTraGo'].get('start_snapshot')
    time_step = end - start
    return time_step
