Add link to dateutil.parser.parse per review comment by @znicholls

doc/source/conf.py

@@ -324,6 +324,7 @@
 # Intersphinx configuration.
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3", None),
+    "dateutil": ("https://dateutil.readthedocs.io/en/stable/", None),
     "numpy": ("https://numpy.org/doc/stable/", None),
     "pandas": ("https://pandas.pydata.org/pandas-docs/stable/", None),
     "pint": ("https://pint.readthedocs.io/en/stable", None),

pyam/core.py

@@ -637,12 +637,20 @@ def swap_time_for_year(self, subannual=False, inplace=False):
         See Also
         --------
         swap_year_for_time
+
         """
         return swap_time_for_year(self, subannual=subannual, inplace=inplace)
 
     def swap_year_for_time(self, inplace=False):
         """Convert the `year` and `subannual` dimensions to `time` (as datetime).
 
+        The method applies :meth:`dateutil.parser.parse` on the combined columns
+        `year` and `subannual`:
+
+        .. code-block:: python
+
+            dateutil.parser.parse([f"{y}-{s}" for y, s in zip(year, subannual)])
+
         Parameters
         ----------
         inplace : bool, optional
@@ -661,6 +669,7 @@ def swap_year_for_time(self, inplace=False):
         See Also
         --------
         swap_time_for_year
+
         """
         return swap_year_for_time(self, inplace=inplace)