pycharm 调试的时候遇到一个比较奇怪的问题

def ElementOperate(driver, elem_name, this_op_dict, dynamic_data_dict=dict(), no_print=False):
   wait_time = 20
   elem = WebDriverWait(driver, 20).until(lambda driver : driver.find_element_by_xpath(xpath))  # 在这行设置条件断点 elem_name = 'xxx' 报错

使用的是 pycharm

elem = WebDriverWait(driver, 20).until(lambda driver : driver.find_element_by_xpath(xpath)) # 在这行设置条件断点 elem_name = 'xxx' 报错

错误信息:

Connected to pydev debugger (build 182.4323.49)

Error while evaluating expression: elem_name == 'search_result_item'

Traceback (most recent call last):

File "C:\Program Files\JetBrains\PyCharm Community Edition 2018.2.3\helpers\pydev_pydevd_bundle\pydevd_frame.py", line 43, in handle_breakpoint_condition

return eval(condition, new_frame.f_globals, new_frame.f_locals)

File "<string>", line 1, in <module></module></string>

NameError: name 'elem_name' is not defined

Backend Qt5Agg is interactive backend. Turning interactive mode on.

1. 排除几个因素, 这个错误应该是在 pycharm 的 debug 预处理类似的时候出现的问题, 问题是在程序运行开始之前发生的

2. 如果把: elem = WebDriverWait(driver, 20).until(lambda driver : driver.find_element_by_xpath(xpath)) 换成一个简单的 print('xxx')则问题不会出现.

3. 把: elem = WebDriverWait(driver, 20).until(lambda driver : driver.find_element_by_xpath(xpath)) 换成: elem = WebDriverWait(driver, 20)问题也不会出现。。。

请问这个是什么问题?有哪位高手了解这个 pycharm 调试机制是什么？ 如何解释这个错误?