pyhton web app model orm poll [TOC] $$ x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a} $$ 13 st=>start: 开始 e=>end: 结束 op=>operation: 我的操作 cond=>condition: 确认? st->op->cond cond(yes)->e cond(no)->op import os print(os.getpid()) print('shshh')