Turn a dictionary into a querystring for a URL.
    
    >>> args = dict(a=1, b=2, c="foo")
    >>> queryjoin(args)
    "a=1&b=2&c=foo"

def queryjoin(argdict=dict(), **kwargs):
    """Turn a dictionary into a querystring for a URL.
    
    >>> args = dict(a=1, b=2, c="foo")
    >>> queryjoin(args)
    "a=1&b=2&c=foo"
    """
    if kwargs: argdict.update(kwargs)
    
    if issubclass(type(argdict), dict):                    
        args = ["{}={}".format(k, v) for k, v in argdict.items() if v != None]
    return "&".join(args)