Add GH # comment in code

Co-authored-by: Kevin Anderson <[email protected]>

Author: AdamRJensen

pvlib/iotools/pvgis.py

@@ -410,7 +410,7 @@ def _coerce_and_roll_tmy(tmy_data, tz, year):
         np.roll(tmy_data, tz, axis=0),
         columns=tmy_data.columns,
         index=new_index)
-    new_tmy_data = \
+    new_tmy_data = \  # GH 2399
         new_tmy_data.astype(dtype=dict(zip(tmy_data.columns, tmy_data.dtypes)))
     return new_tmy_data