Fix flake8 warnings

Author: jhgg

graphql/core/execution/__init__.py

@@ -32,4 +32,4 @@ def execute(schema, root, ast, operation_name='', args=None):
     return e.execute(ast, root, args, operation_name, validate_ast=False)
 
 
-__all__ = ['ExecutionResult', 'Executor', 'execute']
+__all__ = ['ExecutionResult', 'Executor', 'execute']

graphql/core/execution/base.py

@@ -20,6 +20,7 @@
 
 Undefined = object()
 
+
 class ExecutionContext(object):
     """Data that must be available at all points during query execution.