[PyMOL] Color by conservation

[Matzov D. <mat...@we...>]

I'm trying to use the script that is available on pymolwiki for  colouring residues according to conservation. It wasn't very clear to me so I tried to do the given example:
reinitialize
import color_by_conservation

# get some kinases
fetch 1opk 3dtc 3p86 2eva 3efw, async=0

# turn on the sequence viewer
set seq_view

# align them into the "algn" object
for x in cmd.get_names(): cmd.align(x, "3efw and c. A", object="algn")

# color
color_by_conservation aln=algn, as_putty=1

everything went as it should but when it came to the last command pymol gave me this error:  "Bad or incorrectly specified alignment object"

How can I fix this problem?

Thanks