docstr: Return a list of the visible child `.Artist`\s.
code: def get_visible_children(self):
      r"""Return a list of the visible child `.Artist`\s."""
      all_children = (
          self.xline_artists + self.yline_artists + self.label_artists
      )
      return [c for c in all_children if c.get_visible()]
  
imports: import itertools
  import operator
  import warnings
  import matplotlib
  import matplotlib.artist
  import matplotlib.collections
  import matplotlib.text
  import matplotlib.ticker
  import matplotlib.transforms
  import numpy
  import shapely.geometry
  import cartopy
  from cartopy.crs import PlateCarree, Projection, _RectangularProjection
  from cartopy.mpl.ticker import LatitudeFormatter, LatitudeLocator, LongitudeFormatter, LongitudeLocator
label_desc: Use image node_id 26 for calling the Gridliner obj's underlying member method code with example usage: obj.get_visible_children() and returns: unknown