Extract helper methods for building config objects from dicts

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

.pre-commit-config.yaml

@@ -10,7 +10,7 @@
     - id: end-of-file-fixer
     - id: flake8
     - id: name-tests-test
-      exclude: 'tests/integration/testcases.py'
+      exclude: 'tests/(helpers\.py|integration/testcases\.py)'
     - id: requirements-txt-fixer
     - id: trailing-whitespace
 - repo: git://github.com/asottile/reorder_python_imports