Update my_token.move

Author: root28root

mytoken/sources/my_token.move

@@ -5,9 +5,9 @@ module MyToken::coin {
 +    use 0x1::signer;
 
     /// Resource that represents a simple token
-    struct Coin has key {
-        value: u64,
-    }
+    struct Coin has store {
+    value: u64,
+}
 
     const EINSUFFICIENT_BALANCE: u64 = 1;
 
@@ -23,7 +23,7 @@ module MyToken::coin {
 
     /// Transfer tokens
     public fun transfer(from: &mut Coin, amount: u64): Coin {
-        assert!(from.value >= amount, error::invalid_argument(EINSUFFICIENT_BALANCE));
+        assert!(from.value >= amount, EINSUFFICIENT_BALANCE);
         from.value = from.value - amount;
         Coin { value: amount }
     }