def __getitem__(self, key):
        values = dict.__getitem__(self, key.lower())
        if len(values) == 1:
            return values[0]
        else:
            return ", ".join(values)
Get all headers of a certain (case-insensitive) name. If there is
dataset/ETHPy150Open w3c/wptserve/wptserve/request.py/RequestHeaders.__getitem__