ArrayLiteralContentList : ArrayLiteralContent
                            | ArrayLiteralContentList COMMA ArrayLiteralContent

def p_ArrayLiteralContentList(p):
    '''
    ArrayLiteralContentList : ArrayLiteralContent
                            | ArrayLiteralContentList COMMA ArrayLiteralContent
    '''
    if len(p) < 3:
        p[0] = ArrayLiteralContentList(None, p[1])
    else:
        p[0] = ArrayLiteralContentList(p[1], p[3])