title: Warning: Function state mutability can be restricted to pure function
body: <p>I am new to solidity and I have been trying to print out simple messages using functions in solidity, but I have failed to deploy successfully, and there is an error that I can not figure out what's wrong.</p>
  <p>This is what I have tried so far:</p>
  <pre><code> pragma solidity ^0.6.0;
      
      contract test {
          
          string public _feedback;
          
          function reply(string memory feedback) public
          {
             feedback = &quot;Well done!&quot;;
          }
      }
  </code></pre>
  <p>The error I am receiving is &quot;Warning: Function state mutability can be restricted to pure function&quot;</p>