>>> import matplotlib
>>> matplotlib.use("tkagg")
>>> from pylab import *
>>> figure()
<matplotlib.figure.Figure object at 0x103b03150>
>>> line, = plot([1,2,3])
>>> line
<matplotlib.lines.Line2D object at 0x108f81350>
>>> line.set_dashes
<bound method Line2D.set_dashes of <matplotlib.lines.Line2D object at 0x108f81350>>
>>> line.set_dashes('--') # incorrect usage of set_dashes
>>> Exception in Tkinter callback
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 1536, in __call__
    return self.func(*args)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk/Tkinter.py", line 587, in callit
    func(*args)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_tkagg.py", line 370, in idle_draw
    self.draw()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_tkagg.py", line 354, in draw
    FigureCanvasAgg.draw(self)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_agg.py", line 471, in draw
    self.figure.draw(self.renderer)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/artist.py", line 60, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/figure.py", line 1119, in draw
    func(*args)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/artist.py", line 60, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/axes/_base.py", line 2169, in draw
    a.draw(renderer)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/artist.py", line 60, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/lines.py", line 741, in draw
    drawFunc(renderer, gc, tpath, affine.frozen())
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/lines.py", line 1154, in _draw_lines
    self._lineFunc(renderer, gc, path, trans)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/lines.py", line 1201, in _draw_dashed
    renderer.draw_path(gc, path, trans)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-macosx-10.9-x86_64.egg/matplotlib/backends/backend_agg.py", line 166, in draw_path
    self._renderer.draw_path(gc, path, transform, rgbFace)
TypeError: a float is required

>>> plot([1,2,4])
# nothing happens

>>> cla()
# nothing happens