Fix ruff checks

Author: uvilla

python/dolfinx/fem/function.py

@@ -7,6 +7,7 @@
 
 from __future__ import annotations
 
+import warnings
 import typing
 from functools import singledispatch
 

python/test/unit/fem/test_nonlinear_assembler.py

@@ -255,7 +255,9 @@ def F_block(self, snes, x, F):
         for var in self.soln_vars:
             size_local = var.x.petsc_vec.getLocalSize()
             var.x.petsc_vec.array[:] = x_array[offset : offset + size_local]
-            var.x.petsc_vec.ghostUpdate(addv=PETSc.InsertMode.INSERT, mode=PETSc.ScatterMode.FORWARD)
+            var.x.petsc_vec.ghostUpdate(
+                addv=PETSc.InsertMode.INSERT, mode=PETSc.ScatterMode.FORWARD
+                )
             offset += size_local
 
         assemble_vector_block(F, self.L, self.a, bcs=self.bcs, x0=x, scale=-1.0)