'Get whether this node is unbounded I{(a collection)}
@return: True if unbounded, else False.
@rtype: boolean'

def unbounded(self):

    max = self.max
    if (max is None):
        max = '1'
    if max.isdigit():
        return (int(max) > 1)
    else:
        return (max == 'unbounded')
