html页面中的xpath如何提取并使用在selenium中啊

在chrome中安装了XPath Helper的插件，希望提取html页面中的一个img图像，随后通过selenium (python) 选中该img按钮并click()

XPath Helper返回的结果是：
/html[@class='section_header_html_no_scroll']/body[@class='section_header_body_no_scroll']/div[@id='u_knowledge_part.form_scroll']/table[1]/tbody/tr/td/form[@id='u_knowledge_part.do']/span[@id='section_tab.f0fdfd492194d000cde2641d8d46d13f']/span[@id='spacer_section.f0fdfd492194d000cde2641d8d46d13f']/span[@id='f0fdfd492194d000cde2641d8d46d13f']/table[@class='wide']/tbody/tr[1]/td[@class='vsplit'][1]/table[@class='vsplit_bottom_margin']/tbody/tr[@id='element.u_knowledge_part.roles']/td[@class='input_controls']/table/tbody/tr/td[1]/span[@id='u_knowledge_part.roles_edit']/table/tbody/tr[2]/td[@class='bodySmall']/table/tbody/tr[1]/td/a/img/@src

超复杂，直接用find_element_by_xpath果然就报错了，请问我是否该如何处理下这个xpath才能行呢？

>>> a = driver.find_element_by_xpath("/html[@class='section_header_html_no_scro
ll']/body[@class='section_header_body_no_scroll']/div[@id='u_knowledge_part.form
_scroll']/table[1]/tbody/tr/td/form[@id='u_knowledge_part.do']/span[@id='section
_tab.f0fdfd492194d000cde2641d8d46d13f']/span[@id='spacer_section.f0fdfd492194d00
0cde2641d8d46d13f']/span[@id='f0fdfd492194d000cde2641d8d46d13f']/table[@class='w
ide']/tbody/tr[1]/td[@class='vsplit'][1]/table[@class='vsplit_bottom_margin']/tb
ody/tr[@id='element.u_knowledge_part.roles']/td[@class='input_controls']/table/t
body/tr/td[1]/span[@id='u_knowledge_part.roles_edit']/table/tbody/tr[2]/td[@clas
s='bodySmall']/table/tbody/tr[1]/td/a/img/@src")