bump pylint, fix issue 147 (#157)

Author: phanak-sap

dev-requirements.txt

@@ -3,7 +3,7 @@ pytest>=4.6.0
 responses>=0.8.1
 setuptools>=38.2.4
 setuptools-scm>=1.15.6
-pylint==2.6.2
+pylint==2.8.3
 pytest-cov==2.11.1
 codecov==2.1.11
 flake8==3.8.4

pyodata/v2/model.py

@@ -1016,7 +1016,7 @@ def association(self, association_name, namespace=None):
             try:
                 return decl.associations[association_name]
             except KeyError:
-                pass
+                return None
 
     @property
     def associations(self):
@@ -1046,7 +1046,7 @@ def association_set(self, set_name, namespace=None):
             try:
                 return decl.association_sets[set_name]
             except KeyError:
-                pass
+                return None
 
     @property
     def association_sets(self):