for in range( )if isspacefree(boardi)return false return true the last function is isboardfull(this function returns true if the -string list board argument it was passed has an 'xor 'oin every index (except for index which is ignoredif there' at least one space in board that is set to single space then it will return false the for loop will let us check indexes through on the board list as soon as it finds free space on the board (that iswhen isspacefree(boardireturns truethe isboardfull(function will return false if execution manages to go through every iteration of the loopthen none of the spaces are free line will then execute return true the start of the game print('welcome to tic tac toe!'line is the first line that isn' inside of functionso it is the first line of code that executes when you run this program it greets the player while true reset the board theboard [' line ' while loop has true for the condition and will keep looping until the execution encounters break statement line sets up the main tic tac toe board in variable named theboard it is -string listwhere each string is single space rather than type out this full listline uses list replication it is shorter to type [' then [''''''''''deciding the player' mark and who goes first playerlettercomputerletter inputplayerletter(the inputplayerletter(function lets the player type in whether they want to be or the function returns -string listeither [' '' 'or [' '' 'the multiple assignment trick will set playerletter to the first item in the returned list and computerletter to the second