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: Blocking call to retrieve n coordinate pairs through mouse
  clicks.
docstr_tok: ["Blocking","call","to","retrieve","n","coordinate","pairs","through","mouse","clicks","."]
code: def __call__(self, n=1, timeout=30, show_clicks=True):
      """
      Blocking call to retrieve n coordinate pairs through mouse
      clicks.
      """
      self.show_clicks = show_clicks
      self.clicks = []
      self.marks = []
      BlockingInput.__call__(self, n=n, timeout=timeout)
  
      return self.clicks
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import matplotlib.lines
  import logging
label_desc: Use image node_id 12 for calling the BlockingMouseInput obj's underlying member method code with example usage: obj.__call__(n, timeout, show_clicks) and returns: self