class_docstr: Class that creates a callable object to retrieve events in a
  blocking way.
docstr: Blocking call to retrieve n events
docstr_tok: ["Blocking","call","to","retrieve","n","events"]
code: def __call__(self, n=1, timeout=30):
      """
      Blocking call to retrieve n events
      """
  
      if not isinstance(n, int):
          raise ValueError("Requires an integer argument")
      self.n = n
  
      self.events = []
      self.callbacks = []
  
      if hasattr(self.fig.canvas, "manager"):
          # Ensure that the figure is shown, if we are managing it.
          self.fig.show()
  
      # connect the events to the on_event function call
      for n in self.eventslist:
          self.callbacks.append(
              self.fig.canvas.mpl_connect(n, self.on_event)
          )
  
      try:
          # Start event loop
          self.fig.canvas.start_event_loop(timeout=timeout)
      finally:  # Run even on exception like ctrl-c
          # Disconnect the callbacks
          self.cleanup()
  
      # Return the events in this case
      return self.events
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import matplotlib.lines
  import logging
label_desc: Use image node_id 8 for calling the BlockingInput obj's underlying member method code with example usage: obj.__call__(n, timeout) and returns: self