zCluster fails with user-input photometry catalogue

[DavidT3]

The error is:

Traceback (most recent call last):
File "/opt/anaconda3/envs/zcluster/bin/zcluster", line 7, in
exec(compile(f.read(), file, 'exec'))
File "/Users/dt237/software/zCluster/bin/zCluster", line 556, in
extraRetriever, extraOptions, extraPassbandSet=retrievers.getRetriever(args.addExtraPhoto)
File "/Users/dt237/software/zCluster/zCluster/retrievers.py", line 114, in getRetriever
elif database.find("DECaLS") != -1:
AttributeError: 'NoneType' object has no attribute 'find'

It stems from the slightly different treatment of DECaLS in getRetriever - as the value of database being passed into that function is None, rather than a string as is assumed by the use of .find, it just errors.

Replacing line 114 of retrievers.py with:
elif database is not None and database.find("DECaLS") != -1:

Allows it to progress.