Thank you very much for your help. I fixed the script, and it went
through. Now I have a alignment from the three templates.
Then I add my sequence to the alignment using the example of 'align.py'.
And I have a new alignment (see attachment test.ali). In order to
structurally align my sequence with the templates, I try to align the
sequence again using the example of "align2d.py". Here is how I tried:
env = environ()
env.io.atom_files_directory = "./:../atom_files/"
aln = alignment(env)
mdl = model((env, file=('2HI4-1A2', '1PQ2-2C8A', '1OG5-2C9A'),
model_segment=('FIRST:@', 'END:'))