> **Can't find what you're looking for?** Use `search_docs` on the docs MCP server at `https://www.getfoundry.sh/api/mcp` to find what you need.
>
> **Have feedback?** Use `submit_feedback` on the same MCP server.

## `with_key`

### Signature

```solidity
function with_key(StdStorage storage self, address who) internal returns (StdStorage storage);
```

```solidity
function with_key(StdStorage storage self, uint256 amt) internal returns (StdStorage storage);
```

```solidity
function with_key(StdStorage storage self, bytes32 key) internal returns (StdStorage storage);
```

### Description

Passes an argument to the function.

Can be used multiple times to pass multiple arguments. The order matters.

### Examples

```solidity
uint256 slot = stdstore
    .target(addr)
    .sig("fun(uint256,address)")
    .with_key(1)
    .with_key(address(this))
    .find();
```