I am simulating mesi protocol this is my log file, lecturer said "there is small bug", can you spot any bug here, if yes what might be the problem

and following is the mesi protocol code

class MESIProtocol:

def $\_\_$init$\_\_($self$,$ cores$)$:

self.cores $=$ cores

def read$($self$,$ core, address$)$:

sharing$\_$cores $=[$c for c in self.cores if c $!=$ core and self.find$\_$line$\_$in$\_$cache$($c$.$cache, address$)]$

line $=$ self.find$\_$line$\_$in$\_$cache$($core$.$cache, address$)$

if not line:

line $=$ self.load$\_$line$\_$from$\_$memory$($core$,$ address, sharing$\_$cores$)$

if line.state $==\text{'}$I$\text{'}$:

if any$($c$.$cache.find$\_$line$\_$in$\_$cache$($address$).$state $==\text{'}$M$\text{'}$ for c in sharing$\_$cores$)$:

modified$\_$core $=$ next$($c for c in sharing$\_$cores if c$.$cache.find$\_$line$\_$in$\_$cache$($address$).$state $==\text{'}$M$\text{'})$

self.flush$\_$if$\_$modified$($modified$\_$core.cache.find$\_$line$\_$in$\_$cache$($address$))$

modified$\_$core.cache.find$\_$line$\_$in$\_$cache$($address$).$state $=\text{'}$S$\text{'}$

line.state $=\text{'}$S$\text{'}$ if sharing$\_$cores else $\text{'}$E$\text{'}$

return line.value

def write$($self$,$ core, address, value$)$:

self.invalidate$\_$others$($core$,$ address$)$

line $=$ self.find$\_$line$\_$in$\_$cache$($core$.$cache, address$)$

if not line:

line $=$ self.load$\_$line$\_$from$\_$memory$($core$,$ address$)$

if line.state $==\text{'}$E$\text{'}$ or line.state $==\text{'}$S$\text{'}$:

self.flush$\_$if$\_$modified$($line$)$

line.value $=$ value

line.state $=\text{'}$M$\text{'}$

def invalidate$\_$others$($self$,$ core, address$)$:

for other$\_$core in self.cores:

if other$\_$core $!=$ core:

line $=$ self.find$\_$line$\_$in$\_$cache$($other$\_$core.cache, address$)$

if line and line.state $!=\text{'}$I$\text{'}$:

self.flush$\_$if$\_$modified$($line$)$

line.state $=\text{'}$I$\text{'}$

def load$\_$line$\_$from$\_$memory$($self$,$ core, address, sharing$\_$cores$)$:

is$\_$shared $=$ any$($self$.$find$\_$line$\_$in$\_$cache$($c$.$cache, address$)$ for c in sharing$\_$cores if c $!=$ core$)$

line $=$ core.cache.replace$\_$line$($core$.$cache.find$\_$line$($address$),$ address, core.memory.storage$[$address$],$ False$)$

line.state $=\text{'}$S$\text{'}$ if is$\_$shared else $\text{'}$E$\text{'}$

return line

def find$\_$line$\_$in$\_$cache$($self$,$ cache, address$)$:

set$\_$index $=$ cache.find$\_$line$($address$)$

set$\_=$ cache.sets$[$set$\_$index$]$

for line in set$\_$:

if line.address $==$ address and line.valid:

return line

return None

def flush$\_$if$\_$modified$($self$,$ line$)$:

if line.state $==\text{'}$M$\text{'}$:

line.memory.storage$[$line$.$address$]=$ line.value # Flush to memory

line.dirty $=$ False