class_docstr: Class that creates a callable object to retrieve mouse clicks in a
  blocking way.
  
  This class will also retrieve keyboard clicks and treat them like
  appropriate mouse clicks (delete and backspace are like mouse button 3,
  enter is like mouse button 2 and all others are like mouse button 1).
docstr: Process a key click event.  This maps certain keys to appropriate
  mouse click events.
docstr_tok: ["Process","a","key","click","event",".","This","maps","certain","keys","to","appropriate","mouse","click","events","."]
code: def key_event(self):
      """
      Process a key click event.  This maps certain keys to appropriate
      mouse click events.
      """
  
      event = self.events[-1]
      if event.key is None:
          # at least in mac os X gtk backend some key returns None.
          return
  
      key = event.key.lower()
  
      if key in ["backspace", "delete"]:
          self.mouse_event_pop(event)
      elif key in ["escape", "enter"]:
          # on windows XP and wxAgg, the enter key doesn't seem to register
          self.mouse_event_stop(event)
      else:
          self.mouse_event_add(event)
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import matplotlib.lines
  import logging
label_desc: Use image node_id 4 for calling the BlockingMouseInput obj's underlying member method code with example usage: obj.key_event() without return types