def get_constraint_transform_applied_scaling_factor(c, default=None):
    """Get a the scale factor that was used to transform a
    constraint.

    Args:
        c: constraint data object
        default: value to return if no scaling factor exists (default=None)

    Returns:
        The scaling factor that has been used to transform the constraint or the
        default.
    """
    try:
        sf = c.parent_block().constraint_transformed_scaling_factor.get(c, default)
    except AttributeError:
        sf = default # when there is no suffix
    return sf