craftutils.observation.epoch.ImagingEpoch.frame_class.scale_bar(ax: ~matplotlib.axes._axes.Axes, fig: ~matplotlib.figure.Figure, obj: ~typing.Optional[~craftutils.Extragalactic] = None, size: ~astropy.units.quantity.Quantity = <Quantity 1. arcsec>, spread_factor: float = 0.5, x_ax: float = 0.1, y_ax: float = 0.1, line_kwargs: ~typing.Optional[dict] = None, text_kwargs: ~typing.Optional[dict] = None, ext: int = 0, extra_height_top_factor: float = 2.0, bold: bool = False, precision_ang: int = 1, precision_spc: int = 1)