code: def mask_circular_from_shape_pixel_scale_and_radius(shape, pixel_scale, radius_arcsec, centre=(0.0, 0.0)):
      
  
      mask = np.full(shape, True)
  
      centres_arcsec = mask_centres_from_shape_pixel_scale_and_centre(shape=mask.shape, pixel_scale=pixel_scale, centre=centre)
  
      for y in range(mask.shape[0]):
          for x in range(mask.shape[1]):
  
              y_arcsec = (y - centres_arcsec[0]) * pixel_scale
              x_arcsec = (x - centres_arcsec[1]) * pixel_scale
  
              r_arcsec = np.sqrt(x_arcsec ** 2 + y_arcsec ** 2)
  
              if r_arcsec <= radius_arcsec:
                  mask[y, x] = False
  
      return mask
docs: Compute a circular masks from an input masks radius and regular shape.