def modify_fields(**kwargs):
    """
    Allows you to modify certain properties on fields inherited from an abstract superclass
    Usage:
    @modify_fields(timestamp={
        'verbose_name': 'Available From',
        'help_text': 'Earliest date you can book this'})
    class Purchase(BaseOrderItem):
        pass
    """
    def wrap(cls):
        for field, prop_dict in kwargs.items():
            for prop, val in prop_dict.items():
                setattr(cls._meta.get_field(field), prop, val)
        return cls
    return wrap