> ## Documentation Index
> Fetch the complete documentation index at: https://docs.starknet.io/llms.txt
> Use this file to discover all available pages before exploring further.

# core::starknet::storage::storage_base::StorageTraitMut

A trait for creating the struct containing the mutable `StorageBase` or `FlattenedStorage` of
all the members of a contract state.

## Signature

```rust theme={null}
pub trait StorageTraitMut
```

## Trait functions

### storage\_mut

Creates a struct containing a mutable version of the `StorageBase` or `FlattenedStorage` of
all the members of a contract state. Should be called from the `deref` method of the
contract state.

#### Signature

```rust theme={null}
fn storage_mut(self: FlattenedStorage>) -> StorageTraitMutBaseType
```

## Trait types

### BaseType

The type of the struct containing the mutable `StorageBase` or `FlattenedStorage` of all the
members of the type `T`.

#### Signature

```rust theme={null}
type BaseType;
```