STY: style fixes in test variable substitutions

unittests/test_variable_substitutions.py

@@ -39,6 +39,7 @@ def crawler():
                             rfp("test_directories", "example_substitutions", "substitutions.yml"))
     return crawler
 
+
 @pytest.fixture
 def crawler_2():
     crawler = Crawler(debug=True)
@@ -68,6 +69,7 @@ def test_substitutions(crawler):
         assert subd[i]["Project"].get_property(
             "dates").value[0] == "2022-05-12"
 
+
 def test_substitutions_parents(crawler_2):
     # This is a test for:
     # https://gitlab.indiscale.com/caosdb/src/caosdb-crawler/-/issues/35