added helper for returning the first match in an array

This helper would be useful for many of our team's use cases. I know you can just grab the first item manually, but it'd be cleaner to have it in the API.
Please update the docstring to match pep 257

"""
The docstring is a phrase ending in a period. It prescribes the function or method's effect as a command ("Do this", "Return that"), not as a description; e.g. don't write "Returns the pathname ...".
"""