'Provides the values for the given key.
:param str item: key to be looked up
:returns: **str** with the value for the given key
:raises: **ValueError** if the key doesn\'t exist'

def __getitem__(self, item):

    if (item in vars(self)):
        return getattr(self, item)
    else:
        keys = ',    '.join(self.keys())
        raise ValueError(("'%s'    isn't    among    our    enumeration    keys,    which    includes:    %s" % (item, keys)))
