平行趋势检验，前一期不通过，是不是检验不成立？
代码和结果如下
gen policy = year - 2015
tab policy
replace policy = -4 if policy < -4
replace policy =4 if policy > 4
forvalues i = 5(-1)1{
gen pre_`i' = (policy == -`i' & treat == 1)
}
gen current = (policy == 0 & treat == 1)
forvalues j = 1(1)5{
gen post_`j' = (policy == `j' & treat == 1)
}
reghdfe TFP_LP_w pre_4 pre_3 pre_2 current post_1 post_2 post_3 post_4  pre_1 Dual Listage SOE Top5_w Lev_w Cashflow_w Growth_w Roa_w tobin1_w, absorb(code year) cluster(code)
coefplot, baselevels vertical keep(pre_* current post_*) omitted order ( pre_4 pre_3 pre_2 pre_1 current post_1 post_2 post_3 post_4 ) level(95) yline(0,lcolor(edkblue*0.8)) xline(3,lwidth(vthin)lpattern(dash) lcolor(teal)) ylabel(,labsize(*0.75)) xlabel(,labsize(*0.75)) ytitle("政策动态效应",size(small)) xtitle("政策时点",size (small)) addplot(line @b @at) ciopts(lpattern(dash) recast(rcap) msize(medium))msymbol(circle_hollow) scheme(slmono)