Meshvaluecollection

I am having problems with meshvaluecollection.py, in particular, from a file at my disposal that I use to construct D and T tensors from a DTi, I call the function passing

...
mesh = Mesh("brain.xml")
mvc_Dxx = MeshValueCollection("double", mesh, "meshDxx.xml")
...

where mesh is the reconstruction of the brain, and meshDxx.xml is the file to which the xx component of the D tensor has been associated.
Launching this script (defDT.py) I get the following error:

Pre_simulazione lorenzomarta$ python3 defDT.py 
Traceback (most recent call last):
  File "/Users/lorenzomarta/Desktop/Paziente10+4Mesh/Pre_simulazione/defDT.py", line 9, in <module>
    mvc_Dxx = MeshValueCollection("double", mesh, "meshDxx.xml")
  File "/Applications/anaconda3/envs/fenicsproject/lib/python3.10/site-packages/dolfin/mesh/meshvaluecollection.py", line 16, in __new__
    return mvc(mesh, dim)
RuntimeError: 

*** -------------------------------------------------------------------------
*** DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at
***
***     fenics-support@googlegroups.com
***
*** Remember to include the error message listed below and, if possible,
*** include a *minimal* running example to reproduce the error.
***
*** -------------------------------------------------------------------------
*** Error:   Unable to read DOLFIN XML data.
*** Reason:  Unable to find tag <mesh_value_collection>.
*** Where:   This error was encountered inside xmlutils.cpp.
*** Process: 0
*** 
*** DOLFIN version: 2019.1.0
*** Git changeset:  
*** -------------------------------------------------------------------------

(fenicsproject) Mac-2:Pre_simulazione lorenzomarta$ 

How can I solve it?