Fix utcnow warnings

Author: leroyvn

src/joseki/accessor.py

@@ -13,7 +13,7 @@
 from ._version import __version__
 from .constants import AIR_MAIN_CONSTITUENTS_MOLAR_FRACTION, MM, K
 from .profiles.schema import schema
-from .profiles.util import molar_mass
+from .profiles.util import molar_mass, utcnow
 from .units import to_quantity, ureg
 
 logger = logging.getLogger(__name__)
@@ -425,7 +425,7 @@ def rescale(
             raise ValueError("Cannot rescale") from e
 
         # update history attribute
-        now = datetime.datetime.utcnow().replace(microsecond=0).isoformat()
+        now = utcnow()
         for m in factors.keys():
             ds.attrs["history"] += (
                 f"\n{now} - rescaled {m}'s mole fraction using a scaling "
@@ -473,7 +473,7 @@ def drop_molecules(self, molecules: t.List[str]) -> xr.Dataset:
         ds = self._obj
 
         # update history attribute
-        now = datetime.datetime.utcnow().replace(microsecond=0).isoformat()
+        now = utcnow()
 
         ds.attrs["history"] += (
             f"\n{now} - dropped mole fraction data for molecules "

src/joseki/profiles/util.py

@@ -1,6 +1,7 @@
 """Utility module."""
 
 import datetime
+import sys
 import typing as t
 
 import numpy as np
@@ -10,14 +11,22 @@
 from ..constants import MM, K
 from ..units import ureg
 
+if sys.version_info[1] < 11:
 
-def utcnow() -> str:
-    """Get current UTC time.
+    def _utcnow():
+        return datetime.datetime.utcnow()
+else:
 
-    Returns:
-        ISO 8601 formatted UTC timestamp.
-    """
-    return datetime.datetime.utcnow().replace(microsecond=0).isoformat()
+    def _utcnow():
+        return datetime.datetime.now(datetime.UTC)
+
+
+def utcnow(isoformat: bool = True):
+    result = _utcnow()
+    if isoformat:
+        return result.replace(microsecond=0).isoformat()
+    else:
+        return result
 
 
 def number_density(p: pint.Quantity, t: pint.Quantity) -> pint.Quantity: