biopython/biopython — pull request #55 by DavidCain (2012-07-24 10:13:07+00:00)
Title: Simplify Bio.PDB.Selection module

## Summary of changes
* Allow Atoms to be single parameter, as other levels of 'SMCRA' hierarchy can
* Use newer language constructs to de-clutter code, increase speed
* Clean up code to fit PEP 8 guidelines

## Effects, backwards compatibility
The core behavior of Selection is unchanged. The only difference is that a single Atom can now be passed as the `entity_list` instead of converting it to a list first. Accordingly, the code should be backwards-compatible.