def getfirst(obj, uri, strip=True):
    """Return string value of first item returned by obj.get_value(uri).

    By default, strips whitespace surrounding string value.

    If collection is empty, return None.

    """
    data = obj.get_value(uri)

    if data:
        data = str(data[0])

        if strip:
            data = data.strip()

        return data
    else:
        return None