Function Modifiers and reentrancy guard

FunctionModifiersAndReentrancyGuard.sol

  enum MintStage {
        MintLive,
        MintEnded
    }

    MintStage mintStage;
        modifier mintTimedTransitions() {
        if (block.timestamp > endAt)
            nextMintStage();
            _;
    }


    
    modifier atMintStage(MintStage mintStage_) {
        if (mintStage != mintStage_) revert FunctionInvalidAtThisStage();
        _;

    }
   
   //NoReentrant Call function modifier
    bool locked;
   modifier noReentrancy() {
       require(!locked,"Reentrant Call");
       locked = true;
       _;
       locked = false;
       _;
   }

    function nextMintStage() internal {
        mintStage = MintStage(uint(mintStage)+1);
    }