Good morning,

I try to reproduce the fist example of the fenicsx tutorial

I obtained the error message

`AttributeError: module 'dolfinx.mesh' has no attribute 'exterior_facet_indices'`

for the line

` boundary_facets = mesh.exterior_facet_indices(domain.topology)`

I use DOLFINx version: 0.4.1 based on GIT commit: unknown of GitHub - FEniCS/dolfinx: Next generation FEniCS problem solving environment

Here is the script I write

```
from mpi4py import MPI
import numpy
import dolfinx
from dolfinx import mesh
from dolfinx import fem
#
# Dolfinx version
#
print(f"DOLFINx version: {dolfinx.__version__} based on GIT commit: {dolfinx.git_commit_hash} of https://github.com/FEniCS/dolfinx/")
#
# mesh
#
domain = mesh.create_unit_square(MPI.COMM_WORLD, 8, 8, mesh.CellType.quadrilateral)
#
# Spaces
#
V = fem.FunctionSpace(domain, ("CG", 1))
#
# Boundary conditions
#
uD = fem.Function(V)
uD.interpolate(lambda x: 1 + x[0]**2 + 2 * x[1]**2)
#
# Create facet to cell connectivity required to determine boundary facets
#
tdim = domain.topology.dim
fdim = tdim - 1
domain.topology.create_connectivity(fdim, tdim)
boundary_facets = mesh.exterior_facet_indices(domain.topology)
```

And here is the output produced by typing python3 poisson_02.py

```
DOLFINx version: 0.4.1 based on GIT commit: unknown of https://github.com/FEniCS/dolfinx/
Traceback (most recent call last):
File "poisson_02.py", line 29, in <module>
boundary_facets = mesh.exterior_facet_indices(domain.topology)
AttributeError: module 'dolfinx.mesh' has no attribute 'exterior_facet_indices'
```

Thank you

Xavier