Encode the pandas NaT (not-a-time) singleton type (fixes #43)

The pandas package has a singleton pandas.NaT of type pandas.api.typing.NaTType
to represent an entry in a datetime field which is missing/broken/null. A
reasonable encoding is pandas.NaT -> Indeterminate

Author: duetosymmetry

wolframclient/serializers/encoders/pandas.py

@@ -200,3 +200,8 @@ def encode_panda_series(serializer, o):
     if is_legacy_mode():
         return legacy_encode_series(serializer, o)
     return pyarrow_serialize(serializer, o.to_frame())
+
+
+@encoder.dispatch(pandas.NaT)
+def encode_pandas_not_a_time(serializer, o):
+    return serializer.serialize_symbol(b"Indeterminate")

wolframclient/utils/api.py

@@ -153,6 +153,7 @@
     SparseArray="pandas.SparseArray",
     RangeIndex="pandas.RangeIndex",
     ArrowDtype="pandas.ArrowDtype",
+    NaT="pandas.api.typing.NaTType",
 )
 
 pyarrow = API(