def get(using=None):
    """Return a browser launcher instance appropriate for the environment."""
    if using is not None:
        alternatives = [using]
    else:
        alternatives = _tryorder
    for browser in alternatives:
        if '%s' in browser:
            # User gave us a command line, split it into name and args
            browser = shlex.split(browser)
            if browser[-1] == '&':
                return BackgroundBrowser(browser[:-1])
            else:
                return GenericBrowser(browser)
        else:
            # User gave us a browser name or path.
            try:
                command = _browsers[browser.lower()]
            except __HOLE__:
                command = _synthesize(browser)
            if command[1] is not None:
                return command[1]
            elif command[0] is not None:
                return command[0]()
    raise Error("could not locate runnable browser")

# Please note: the following definition hides a builtin function.
# It is recommended one does "import webbrowser" and uses webbrowser.open(url)
# instead of "from webbrowser import *".
dataset/ETHPy150Open deanhiller/databus/webapp/play1.3.x/python/Lib/webbrowser.py/get