InClassDefList : InClassDef
                   | InClassDefList InClassDef

def p_InClassDefList(p):
    '''
    InClassDefList : InClassDef
                   | InClassDefList InClassDef
    '''
    if len(p) < 3:
        p[0] = InClassDefList(None, p[1])
    else:
        p[0] = InClassDefList(p[1], p[2])