title: Solidity Error for data location part. How to solve the error?
body: <p>from solidity:
  TypeError: Data location must be &quot;storage&quot;, &quot;memory&quot; or &quot;calldata&quot; for variable, but none was given</p>
  <pre><code>function transfer(address user, uint256 id, uint256 qty) public view returns(){
      deposit = deposit[user][id];
  }
  </code></pre>