Traceback Error

<matplotlib.colorbar.Colorbar object at 0x7f8866c687d0>
Error in lines 31-31
Traceback (most recent call last):
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/smc_sagews/sage_server.py", line 968, in execute
    exec compile(block+'\n', '', 'single') in namespace, locals
  File "", line 1, in <module>
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/smc_sagews/sage_salvus.py", line 3532, in _show_pyplot
    matplotlib.pyplot.savefig(filename)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/pyplot.py", line 688, in savefig
    res = fig.savefig(*args, **kwargs)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1565, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/backend_bases.py", line 2232, in print_figure
    **kwargs)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/backends/backend_svg.py", line 1206, in print_svg
    return self._print_svg(filename, svgwriter, fh_to_close, **kwargs)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/backends/backend_svg.py", line 1234, in _print_svg
    self.figure.draw(renderer)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 61, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1159, in draw
    func(*args)
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/mpl_toolkits/mplot3d/axes3d.py", line 263, in draw
    self.M = self.get_proj()
  File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/matplotlib-1.5.1-py2.7-linux-x86_64.egg/mpl_toolkits/mplot3d/axes3d.py", line 981, in get_proj
    xp = R[0] + np.cos(razim) * np.cos(relev) * self.dist
AttributeError: 'Float' object has no attribute 'cos'