# API Changes for 3.4.2

## Behaviour changes

### Rename first argument to `subplot_mosaic`

Both [.Figure.subplot_mosaic]{.title-ref}, and
[.pyplot.subplot_mosaic]{.title-ref} have had the first position
argument renamed from *layout* to *mosaic*. This is because we are
considering to consolidate *constrained_layout* and *tight_layout*
keyword arguments in the Figure creation functions of
[.pyplot]{.title-ref} into a single *layout* keyword argument which
would collide.

As this API is provisional, we are changing this with no deprecation
period.