我需要使用键盘操作来验证下拉框。我写了脚本，但是抛出错误
*** Variables ***
${dropdown_button} css=.list > div:nth-child(2) > div:nth-child(1) > div:nth-child(3) > div:nth-child(1) > combo-box:nth-child(1) > div:nth-child(1) > div:nth-child(1) > div:nth-child(2) > mat-icon:nth-child(1) > svg:nth-child(1)
${dropdown_list_1} css=.list > div:nth-child(2) > div:nth-child(1) > div:nth-child(3) > div:nth-child(1) > combo-box:nth-child(1) > div:nth-child(1) > div:nth-child(2) > div:nth-child(1)
${dropdown_list_2} css=.list > div:nth-child(2) > div:nth-child(1) > div:nth-child(3) > div:nth-child(1) > combo-box:nth-child(1) > div:nth-child(1) > div:nth-child(2) > div:nth-child(2)
${dropdown_list_3} css=.list > div:nth-child(2) > div:nth-child(1) > div:nth-child(3) > div:nth-child(1) > combo-box:nth-child(1) > div:nth-child(1) > div:nth-child(2) > div:nth-child(3)
*** Keywords ***
Click Element "${dropdown_button}"
Sleep 3s
Press Key ${dropdown_list_1} \ue015 #Down arrow
Press Key ${dropdown_list_2} \ue015 #Down arrow
Press Key ${dropdown_list_3} \ue013 #up arrow
Press Key ${dropdown_list_2} \ue007 #Pressing enter