I have a 2d function with four poles that i would like to exclude from the plot because they hide interesting details of the rest of the plot. With just one pole i can omit one region. Now I want to omit all four like this:

```
show( contour_plot(pic, (x,-0.5,1.5), (z,-1,2), region=[((x)^2+(z)^2-.01), ((x)^2+(z-1)^2-.01), ((x-1)^2+(z)^2-.01), ((x-1)^2+(z-1)^2-.01)] ) )
```

that means i give a list of regions. That fails:

```
Traceback (most recent call last):
File "e-feld.sage.py", line 68, in <module>
show( contour_plot(pic, (x,-_sage_const_0p5 ,_sage_const_1p5 ), (z,-_sage_const_1 ,_sage_const_2 ), region=[((x)**_sage_const_2 +(z)**_sage_const_2 -_sage_const_p01 ), ((x)**_sage_const_2 +(z-_sage_const_1 )**_sage_const_2 -_sage_const_p01 ), ((x-_sage_const_1 )**_sage_const_2 +(z)**_sage_const_2 -_sage_const_p01 ), ((x-_sage_const_1 )**_sage_const_2 +(z-_sage_const_1 )**_sage_const_2 -_sage_const_p01 )] ) )
File "/usr/lib/python2.7/dist-packages/sage/misc/decorators.py", line 411, in wrapper
return func(*args, **kwds)
File "/usr/lib/python2.7/dist-packages/sage/misc/decorators.py", line 411, in wrapper
return func(*args, **kwds)
File "/usr/lib/python2.7/dist-packages/sage/misc/decorators.py", line 492, in wrapper
return func(*args, **options)
File "/usr/lib/python2.7/dist-packages/sage/plot/contour_plot.py", line 848, in contour_plot
include_endpoint=True)],
TypeError: 'tuple' object is not callable
```

Is it my syntax? Can I give a list of regions, at all? Or can I tone down the poles in some other way so that i can still see the contours of my plot?