Matplotlib imshow() too many objects for cmap

Matplotlib imshow() too many objects for cmap

I'm trying to create a simple imshow() plot (matplotlib v.1.2.1) of a 2D
gaussian function:
import matplotlib.pyplot as plt
import numpy as np
from pylab import *
def gaussian(x,y,stdx,stdy):
return 1.0/(2*np.pi*stdx*stdy) * (np.exp(-0.5*(x**2/stdx**2 +
y**2/stdy**2)))
coords = np.linspace(-1,1,100)
X,Y = np.meshgrid(coords,coords)
std_list = np.linspace(1,2,20)
output = [gaussian(X,Y,std_list[i],std_list[i]) for i in
range(len(std_list))]
for i in range(len(output)):
plt.imshow(X,Y,np.array(output[i]),cmap='bone')
plt.show()
And I get the following error:
Traceback (most recent call last):
File "blur.py", line 14, in <module>
plt.imshow(X,Y,np.array(output[i]),cmap='bone')
TypeError: imshow() got multiple values for keyword argument 'cmap'
In fact, to make sure I wasn't crazy, I took out the cmap argument
altogether, and now I'm getting the following error:
Traceback (most recent call last):
File "blur.py", line 14, in <module>
plt.imshow(X,Y,np.array(output[i]))
File
"/home/username/anaconda/lib/python2.7/site-packages/matplotlib/pyplot.py",
line 2737, in imshow
imlim=imlim, resample=resample, url=url, **kwargs)
File
"/home/username/anaconda/lib/python2.7/site-packages/matplotlib/axes.py",
line 7098, in imshow
if norm is not None: assert(isinstance(norm, mcolors.Normalize))
AssertionError
I've made sure that the arguments of imshow( ) all have the same shape, so
I'm not entirely sure what I'm doing wrong. Could this be a bug?