Integrate lambdawarmer with zappa

zappa_lambdawarmer.diff

--- unzipped2/zappa/handler.py	1980-01-01 00:00:00.000000000 +0100
+++ unzipped/zappa/handler.py	2019-02-28 11:04:44.445385373 +0100
@@ -576,9 +576,15 @@
             return content
 
 
-def lambda_handler(event, context):  # pragma: no cover
-    return LambdaHandler.lambda_handler(event, context)
+try:
+    import lambdawarmer
 
+    @lambdawarmer()
+    def lambda_handler(event, context):  # pragma: no cover
+        return LambdaHandler.lambda_handler(event, context)
+except:  # pragma: no cover
+    def lambda_handler(event, context):  # pragma: no cover
+        return LambdaHandler.lambda_handler(event, context)
 
 def keep_warm_callback(event, context):
     """Method is triggered by the CloudWatch event scheduled when keep_warm setting is set to true."""