class_docstr: Click on a point to select and highlight it -- the data that
  generated the point will be shown in the lower Axes.  Use the 'n'
  and 'p' keys to browse through the next and previous points
class_docstr_tok: ["Click","on","a","point","to","select","and","highlight","it","--","the","data","that","generated","the","point","will","be","shown","in","the","lower","Axes",".","Use","the","'n'","and","'","p","'","keys","to","browse","through","the","next","and","previous","points"]
code: def on_press(self, event):
      if self.lastind is None:
          return
      if event.key not in ("n", "p"):
          return
      if event.key == "n":
          inc = 1
      else:
          inc = -1
  
      self.lastind += inc
      self.lastind = np.clip(self.lastind, 0, len(xs) - 1)
      self.update()
  
imports: import numpy
label_desc: Use image node_id 2 for calling the PointBrowser obj's underlying member method code with example usage: obj.on_press(event) without return types