Except unit uni pint quantity.

dev-requirements.txt

@@ -36,6 +36,10 @@ distlib==0.3.9
     # via virtualenv
 filelock==3.16.1
     # via virtualenv
+flexcache==0.3
+    # via pint
+flexparser==0.4
+    # via pint
 fonttools==4.55.2
     # via matplotlib
 ghp-import==2.1.0
@@ -135,9 +139,12 @@ pathspec==0.12.1
     #   mkdocs-macros-plugin
 pillow==11.0.0
     # via matplotlib
+pint==0.24.4
+    # via pynxtools (pyproject.toml)
 platformdirs==4.3.6
     # via
     #   mkdocs-get-deps
+    #   pint
     #   virtualenv
 pluggy==1.5.0
     # via pytest
@@ -204,7 +211,11 @@ types-pyyaml==6.0.12.20240917
 types-requests==2.32.0.20241016
     # via pynxtools (pyproject.toml)
 typing-extensions==4.12.2
-    # via mypy
+    # via
+    #   flexcache
+    #   flexparser
+    #   mypy
+    #   pint
 tzdata==2024.2
     # via pandas
 urllib3==2.2.3

pyproject.toml

@@ -35,6 +35,7 @@ dependencies = [
     "importlib-metadata",
     "lxml>=4.9.1",
     "anytree",
+    "pint>=0.17",
 ]
 
 [project.urls]

src/pynxtools/dataconverter/writer.py

@@ -21,11 +21,11 @@
 
 import copy
 import logging
-import sys
 import xml.etree.ElementTree as ET
 
 import h5py
 import numpy as np
+import pint
 
 from pynxtools.dataconverter import helpers
 from pynxtools.dataconverter.exceptions import InvalidDictProvided
@@ -35,7 +35,7 @@
 )
 
 logger = logging.getLogger("pynxtools")  # pylint: disable=C0103
-
+ureg = pint.UnitRegistry()
 
 def does_path_exist(path, h5py_obj) -> bool:
     """Returns true if the requested path exists in the given h5py object."""
@@ -259,8 +259,22 @@ def _put_data_into_hdf5(self):
 
         def add_units_key(dataset, path):
             units_key = f"{path}/@units"
-            if units_key in self.data.keys() and self.data[units_key] is not None:
-                dataset.attrs["units"] = self.data[units_key]
+            units = self.data.get(units_key, None)
+            if units is None:
+                return
+            if isinstance(units, pint.Unit):
+                units = str(units)
+            else:
+                try:
+                    ureg.Unit(units)
+                except pint.errors.UndefinedUnitError as exc:
+                    massage = (
+                        f"Units provided for path: '{path}@units' are not valid."
+                        f" Please provide a valid unit."
+                    )
+                    raise InvalidDictProvided(massage) from exc
+
+            dataset.attrs["units"] = units
 
         for path, value in self.data.items():
             try: