Cleanup trailing whitespaces

assets/eip-4907/contracts/ERC4907.sol

@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: CC0-1.0
-pragma solidity ^0.8.0; 
+pragma solidity ^0.8.0;
 
 import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 import "./IERC4907.sol";
 
 contract ERC4907 is ERC721, IERC4907 {
-    struct UserInfo 
+    struct UserInfo
     {
         address user;   // address of user role
         uint64 expires; // unix timestamp, user expires
@@ -15,11 +15,11 @@ contract ERC4907 is ERC721, IERC4907 {
 
     constructor(string memory name_, string memory symbol_)
      ERC721(name_,symbol_)
-     {         
+     {
      }
-    
+
     /// @notice set the user and expires of a NFT
-    /// @dev The zero address indicates there is no user 
+    /// @dev The zero address indicates there is no user
     /// Throws if `tokenId` is not valid NFT
     /// @param user  The new user of the NFT
     /// @param expires  UNIX timestamp, The new user could use the NFT before expires
@@ -37,15 +37,15 @@ contract ERC4907 is ERC721, IERC4907 {
     /// @return The user address for this NFT
     function userOf(uint256 tokenId)public view virtual returns(address){
         if( uint256(_users[tokenId].expires) >=  block.timestamp){
-            return  _users[tokenId].user; 
+            return  _users[tokenId].user;
         }
         else{
             return address(0);
         }
     }
 
     /// @notice Get the user expires of an NFT
-    /// @dev The zero value indicates that there is no user 
+    /// @dev The zero value indicates that there is no user
     /// @param tokenId The NFT to get the user expires for
     /// @return The user expires for this NFT
     function userExpires(uint256 tokenId) public view virtual returns(uint256){
@@ -69,5 +69,4 @@ contract ERC4907 is ERC721, IERC4907 {
             emit UpdateUser(tokenId, address(0), 0);
         }
     }
-} 
-
+}

assets/eip-4907/contracts/ERC4907Demo.sol

@@ -1,18 +1,18 @@
 // SPDX-License-Identifier: CC0-1.0
-pragma solidity ^0.8.0; 
+pragma solidity ^0.8.0;
 
 import "./ERC4907.sol";
 
 contract ERC4907Demo is ERC4907 {
 
     constructor(string memory name_, string memory symbol_)
      ERC4907(name_,symbol_)
-     {         
+     {
      }
 
     function mint(uint256 tokenId, address to) public {
         _mint(to, tokenId);
     }
 
-} 
+}
 

assets/eip-4907/contracts/IERC4907.sol

@@ -9,7 +9,7 @@ interface IERC4907 {
     event UpdateUser(uint256 indexed tokenId, address indexed user, uint64 expires);
 
     /// @notice set the user and expires of a NFT
-    /// @dev The zero address indicates there is no user 
+    /// @dev The zero address indicates there is no user
     /// Throws if `tokenId` is not valid NFT
     /// @param user  The new user of the NFT
     /// @param expires  UNIX timestamp, The new user could use the NFT before expires
@@ -22,7 +22,7 @@ interface IERC4907 {
     function userOf(uint256 tokenId) external view returns(address);
 
     /// @notice Get the user expires of an NFT
-    /// @dev The zero value indicates that there is no user 
+    /// @dev The zero value indicates that there is no user
     /// @param tokenId The NFT to get the user expires for
     /// @return The user expires for this NFT
     function userExpires(uint256 tokenId) external view returns(uint256);

assets/eip-4907/migrations/1_initial_migration.js

@@ -1,6 +1,5 @@
 const ERC4907Demo = artifacts.require("ERC4907Demo");
 
 module.exports = function (deployer) {
-  deployer.deploy(ERC4907Demo,'ERC4907Demo','ERC4907Demo');  
+  deployer.deploy(ERC4907Demo, "ERC4907Demo", "ERC4907Demo");
 };
-

assets/eip-4907/truffle-config.js

@@ -81,30 +81,31 @@ module.exports = {
   // Configure your compilers
   compilers: {
     solc: {
-      version: "0.8.10",    // Fetch exact version from solc-bin (default: truffle's version)
+      version: "0.8.10", // Fetch exact version from solc-bin (default: truffle's version)
       // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
-      settings: {          // See the solidity docs for advice about optimization and evmVersion
-       optimizer: {
-         enabled: false,
-         runs: 200
-       }
-      //  ,
-      //  evmVersion: "byzantium"
-      // }
-    }
-  },
+      settings: {
+        // See the solidity docs for advice about optimization and evmVersion
+        optimizer: {
+          enabled: false,
+          runs: 200,
+        },
+        //  ,
+        //  evmVersion: "byzantium"
+        // }
+      },
+    },
 
-  // Truffle DB is currently disabled by default; to enable it, change enabled:
-  // false to enabled: true. The default storage location can also be
-  // overridden by specifying the adapter settings, as shown in the commented code below.
-  //
-  // NOTE: It is not possible to migrate your contracts to truffle DB and you should
-  // make a backup of your artifacts to a safe location before enabling this feature.
-  //
-  // After you backed up your artifacts you can utilize db by running migrate as follows: 
-  // $ truffle migrate --reset --compile-all
-  //
-  // db: {
+    // Truffle DB is currently disabled by default; to enable it, change enabled:
+    // false to enabled: true. The default storage location can also be
+    // overridden by specifying the adapter settings, as shown in the commented code below.
+    //
+    // NOTE: It is not possible to migrate your contracts to truffle DB and you should
+    // make a backup of your artifacts to a safe location before enabling this feature.
+    //
+    // After you backed up your artifacts you can utilize db by running migrate as follows:
+    // $ truffle migrate --reset --compile-all
+    //
+    // db: {
     // enabled: false,
     // host: "127.0.0.1",
     // adapter: {
@@ -113,5 +114,5 @@ module.exports = {
     //     directory: ".db"
     //   }
     // }
-  }
+  },
 };