def default_narrative(
        end_yr,
        value_by,
        value_ey,
        diffusion_choice='linear',
        sig_midpoint=0,
        sig_steepness=1,
        base_yr=2015,
        regional_specific=True,
        fueltype_replace=0,
        fueltype_new=0,
    ):
    """Create a default single narrative with a single timestep

    E.g. from value 0.2 in 2015 to value 0.5 in 2050

    Arguments
    ----------
    end_yr : int
        End year of narrative
    value_by : float
        Value of start year of narrative
    value_ey : float
        Value at end year of narrative
    diffusion_choice : str, default='linear'
        Wheter linear or sigmoid
    sig_midpoint : float, default=0
        Sigmoid midpoint
    sig_steepness : float, default=1
        Sigmoid steepness
    base_yr : int
        Base year
    regional_specific : bool
        If regional specific or not

    Returns
    -------
    container : list
        List with narrative
    """
    return [{
        'base_yr': base_yr,
        'end_yr': end_yr,
        'value_by': value_by,
        'value_ey': value_ey,
        'diffusion_choice': diffusion_choice,
        'sig_midpoint': sig_midpoint,
        'sig_steepness': sig_steepness,
        'regional_specific': regional_specific,
        'fueltype_replace': fueltype_replace,
        'fueltype_new': fueltype_new
        }]