# Adding principal component to collection returns an error

## Tags
* assigned: alex
* status: unclear
* priority: high
* type: bug
* keywords: collections, from github

## Members

* rupertoverall

## Description

=> https://github.com/genenetwork/genenetwork2/issues/559 From GitHub

### Describe the bug

When calcuating principal components from a correlation matrix, attempting to add one or more PCs to the collection returns the following error:

```

      GeneNetwork tux01:gene:2.11-rc2-testing-73131a84f  http://www.genenetwork.org/collections/view?uc_id=a7e8dce1-f6a3-464d-85eb-e5a7696ce0b6 (12:12PM UTC Mar 01, 2021)
       Traceback (most recent call last):
         File "/usr/local/guix-profiles/gn-latest-20201216/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
           rv = self.dispatch_request()
         File "/usr/local/guix-profiles/gn-latest-20201216/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
           return self.view_functions[rule.endpoint](**req.view_args)
         File "/export/local/home/gn2/production/gene/wqflask/wqflask/collect.py", line 194, in view_collection
           name, dataset_name = atrait.split(':')
       ValueError: not enough values to unpack (expected 2, got 1)

```

### To Reproduce

* Add transcript traits to a collection.
* Calculate the correlation matrix.
* Select One or more principal components.
* Click 'Add' to add this to the collection.
NOTE: This was done with the 'BXD Aged hippocampus individual data' dataset (GN712).

### Expected behavior
The PC should be treated as a normal trait and added to the collection.

### Screenshots

Environment setup (please complete the following information):
Run on 'http://www.genenetwork.org/' through Firefox on MacOS Mojave.