def get_release_date ():
    """Parse and return relase date as string from doc/changelog.txt."""
    fname = os.path.join("doc", "changelog.txt")
    release_date = "unknown"
    with open(fname) as fd:
        # the release date is on the first line
        line = fd.readline()
        mo = release_ro.search(line)
        if mo:
            release_date = mo.groups(1)
    return release_date
Parse and return relase date as string from doc/changelog.txt.