尝试从自定义库访问关键字时,显示错误InvalidArgumentException

我使用下面的文件夹结构来维护我的测试脚本

Test_Scripts

    TestCase
        TestSuite1.robot

    SupportFiles
        RF_CustomLibrary.py

测试套件1.robot

*** Settings ***
Library                             SeleniumLibrary
Library                            ..\\SupportFiles\\RF_CustomLibrary.py

*** Variables ***
${Browser}     Chrome

*** Test cases ***

Sample Test Case
    Verify Paste text functionality

*** Keywords ***
Verify Paste text functionality
    Set Library Search Order    RF_CustomLibrary
    Open Browser    https://gmail.com    ${BROWSER}
    Sleep    2s
    Maximize Browser Window
    Wait Until Keyword Succeeds    60s     2s   Element Should Be Visible       ${L_Login_btn}
    PasteTextFunction    id=identifierId    Username1

自定义库:RF_CustomLibrary.py

import os
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from SeleniumLibrary import SeleniumLibrary
from SeleniumLibrary.base import LibraryComponent, keyword
from SeleniumLibrary.errors import ElementNotFound
from SeleniumLibrary.utils import is_noney


class RF_CustomLibrary(SeleniumLibrary):

    @keyword
    def pasteTextFunction(self, locator, text):
        os.system("echo off | clip")
        os.system("echo %s| clip" % text.strip())
        element = self._current_browser().find_element(locator)
        element.clear()
        element.send_keys(Keys.CONTROL, 'v')

当我执行此测试用例时,将为关键字“显示以下错误消息” PasteTextFunction函数 "

InvalidArgumentException: Message: invalid argument: invalid locator

任何解决此错误的建议/输入都会很有帮助。