# Objective
- Fixes#16861
## Solution
- Added:
- `UnsafeEntityCell::get_mut_assume_mutable_by_id`
- `EntityMut::get_mut_assume_mutable_by_id`
- `EntityMut::get_mut_assume_mutable_by_id_unchecked`
- `EntityWorldMut::into_mut_assume_mutable_by_id`
- `EntityWorldMut::into_mut_assume_mutable`
- `EntityWorldMut::get_mut_assume_mutable_by_id`
- `EntityWorldMut::into_mut_assume_mutable_by_id`
- `EntityWorldMut::modify_component_by_id`
- `World::modify_component_by_id`
- `DeferredWorld::modify_component_by_id`
- Added `fetch_mut_assume_mutable` to `DynamicComponentFetch` trait
(this is a breaking change)
## Testing
- CI
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## Migration Guide
If you had previously implemented `DynamicComponentFetch` you must now
include a definition for `fetch_mut_assume_mutable`. In general this
will be identical to `fetch_mut` using the relevant alternatives for
actually getting a component.
---
## Notes
All of the added methods are minor variations on existing functions and
should therefore be of low risk for inclusion during the RC process.
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