fix open for py35

* also add references header in pvgis.py

Author: mikofski

pvlib/iotools/pvgis.py

@@ -71,9 +71,13 @@ def get_pvgis_tmy(lat, lon, outputformat='json', usehorizon=True,
         the error message in the response will be raised as an exception,
         otherwise raise whatever ``HTTP/1.1`` error occurred
 
+    References
+    ----------
+    
     .. [1] `PVGIS <https://ec.europa.eu/jrc/en/pvgis>`_
     .. [2] `PVGIS TMY tool <https://ec.europa.eu/jrc/en/PVGIS/tools/tmy>`_
-    .. [3] `PVGIS horizon profile tool <https://ec.europa.eu/jrc/en/PVGIS/tools/horizon>`_
+    .. [3] `PVGIS horizon profile tool
+       <https://ec.europa.eu/jrc/en/PVGIS/tools/horizon>`_
     """
     # use requests to format the query string by passing params dictionary
     params = {'lat': lat, 'lon': lon, 'outputformat': outputformat}

pvlib/test/test_pvgis.py

@@ -60,7 +60,7 @@ def epw_meta():
 
 @pytest.fixture
 def meta_expected():
-    with open(DATA / 'pvgis_tmy_meta.json') as f:
+    with (DATA / 'pvgis_tmy_meta.json').open() as f:
         return json.load(f)