ci: build issues

appveyor.yml

@@ -11,11 +11,8 @@ environment:
     secure: Ry77Jz+ZhUApoPN/x3oOxDjDWhDXYwWCakp7ak0uiDExS97/wqVpZ5PZzKq3Liof
   PYPI_USR: ci_afm
   matrix:
-    - PYTHON: "C:\\Python36"
     - PYTHON: "C:\\Python36-x64"
-    - PYTHON: "C:\\Python37"
     - PYTHON: "C:\\Python37-x64"
-    - PYTHON: "C:\\Python38"
     - PYTHON: "C:\\Python38-x64"
 
 install:

tests/test_model_style.py

@@ -34,7 +34,8 @@ def test_model_parameter_names():
         md = model.models_available[key]
         for key2, nn in zip(md.parameter_keys, md.parameter_names):
             if key2 in NAME_MAPPING:
-                assert nn in NAME_MAPPING[key2], "bad {} in {}".format(key2, md)
+                assert nn in NAME_MAPPING[key2], "bad {} in {}".format(
+                    key2, md)
             else:
                 msg = "Parameter {} not registered for test!".format(key2)
                 assert False, msg
@@ -45,7 +46,8 @@ def test_model_parameter_units():
         md = model.models_available[key]
         for key2, un in zip(md.parameter_keys, md.parameter_units):
             if key2 in UNIT_MAPPING:
-                assert UNIT_MAPPING[key2] == un, "bad {} in {}".format(key2, md)
+                assert UNIT_MAPPING[key2] == un, "bad {} in {}".format(
+                    key2, md)
             else:
                 msg = "Parameter {} not registered for test!".format(key2)
                 assert False, msg