may you make my code more efficient without using pure eliminataion, in additon could you possibly make it output $-1$ instead of $1,$ False in the list of list :

def unit$\_$propagation$($clauses$,$ assignment$)$:

unit$\_$clauses $=[$c for c in clauses if len$($c$)==1]$

while unit$\_$clauses:

unit $=$ unit$\_$clauses.pop$()$

literal $=$ next$($iter$($unit$))$

value $=$ literal $>0$

assignment$[$abs$($literal$)]=$ value

clauses $=$ update$\_$clauses$($clauses$,$ literal$)$

if clauses is False:

return False, assignment

unit$\_$clauses $=[$c for c in clauses if len$($c$)==1]$

return clauses, assignment

def update$\_$clauses$($clauses$,$ literal$)$:

updated$\_$clauses $=[]$

for clause in clauses:

if literal in clause:

continue

new$\_$clause $=[$x for x in clause if x $!=-$literal$]$

if not new$\_$clause:

return False

updated$\_$clauses.append$($new$\_$clause$)$

return updated$\_$clauses

def dpll$\_$sat$\_$solve$($clauses$,$ assignment$=())$:

clauses, assignment $=$ unit$\_$propagation$($clauses$,$ assignment$)$

if clauses is False:

return False

if all$($len$($clause$)==0$ for clause in clauses$)$:

return $[$list$($k$)$ for k in sorted$($assignment$.$items$())]$

unassigned$\_$vars $=\{$abs$($literal$)$ for clause in clauses for literal in clause if abs$($literal$)$ not in assignment$\}$

if not unassigned$\_$vars:

return $[$list$($k$)$ for k in sorted$($assignment$.$items$())]$

var $=$ unassigned$\_$vars.pop$()$

for value in $[$True$,$ False$]$:

new$\_$assignment $=$ assignment.copy$()$

new$\_$assignment$[$var$]=$ value

result $=$ dpll$\_$sat$\_$solve$($update$\_$clauses$($clauses$,$ var$)$ if value else update$\_$clauses$($clauses$,-$var$),$ new$\_$assignment$)$

if result is not False:

return result

return False