allow hpc_service and rr_service to be None when calling write_slices_file
diff --git a/planetstack/hpc_observer/hpclib.py b/planetstack/hpc_observer/hpclib.py
index e91a468..5375c2f 100644
--- a/planetstack/hpc_observer/hpclib.py
+++ b/planetstack/hpc_observer/hpclib.py
@@ -62,14 +62,18 @@
 
         return mapping
 
-    def write_slices_file(self, hpc_service, rr_service):
+    def write_slices_file(self, hpc_service=None, rr_service=None):
+        if (hpc_service is None):
+            hpc_service = HpcService.objects.get()
+
+        if (rr_service is None):
+            rr_service = RequestRouterService.objects.get()
+
         mapping = self.extract_slice_info(hpc_service)
         rr_mapping = self.extract_slice_info(rr_service)
 
         mapping.update(rr_mapping)
 
-        print mapping
-
         fn = "/tmp/slices"
 
         f = open(fn, "w")
@@ -95,9 +99,7 @@
 """ % mapping)
 
 if __name__ == '__main__':
-    hpc_service = HpcService.objects.get()
-    rr_service = RequestRouterService.objects.get()
     lib = HpcLibrary()
-    lib.write_slices_file(hpc_service, rr_service)
+    lib.write_slices_file()