Can't set colormap index using color name

[chaosphere2112]

import vcs
cmap = vcs.createcolormap()
cmap.index[5] = "blue"

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/uvcdat/2.4.0/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/vcs/colormap.py", line 170, in __setitem__
    'Must be either a list object, tuple object, or integer value.')
ValueError: Must be either a list object, tuple object, or integer value.

Migrated from: https://github.com/UV-CDAT/uvcdat/issues/1860