'Return methods with the name starting with prefname.'

def _get_infoset(self, prefname):

    infoset = []
    excludes = (('%sinfoset' % prefname),)
    preflen = len(prefname)
    for name in dir(self.__class__):
        if (name.startswith(prefname) and (name not in excludes)):
            member = getattr(self.__class__, name)
            if isinstance(member, MethodType):
                infoset.append(name[preflen:].replace('_', '    '))
    return infoset
